Nicotine Gum Side Effects: Stories From Long Term Users


by James Bickford

Updated: April 4, 2022

nicotine gum side effects

Most medicines cause side effects, but the hope is that the medicine will give you more positive relief from your problem than harm. The most common side effects of nicotine gum are dizziness, increased blood pressure, fast heart beating, insomnia, nausea, cough, vomiting, and more.

Probably, vaping devices can make you feel like you are smoking a cigarette without any of the negative consequences, but it is still not 100% safe or without risks.

There have been many reports of short-term and long-term nicotine gum side effects by users. They range from the bizarre (crazy dreams) to the very scary (hair loss, stomach ulcers). We’ve collected some information on some of the reported gum side effects.

What Are the Long-Term Side Effects of Nicotine Gum?

There are several side effects that could be experienced:

  • Fatigue
  • Headaches
  • Dizziness
  • Increased heart rate
  • Salivating
  • Dry throat
  • Restlessness
  • Anxiety
  • Difficulty in sleeping
  • Depression
  • Irritability

These symptoms are quite common and not serious. They will go away, but if they do not, contact a doctor.

Other side effects are increased appetite and weight gain. These side effects can be mitigated through diet and exercise.

Nicotine Gum User Reviews

Nausea and Nightmares

Nicotine gum side effects can cause nausea and uncomfortable stomach pains.

‘I actually smoked when I used the gum. A lot of the time I felt the need to throw up

a 25-year-old entrepreneur claims.

He argues that one of the main problems with gum is that there is far too much nicotine within it. This sends the body into shock and causes nausea. This is the body’s response when there are toxins in your bloodstream – you get a similar reaction if you drink too much alcohol.

‘The worse complaint I hear is people experiencing nightmares or strange dreams.

Says a male entrepreneur. He adds that he suffered from such problems himself whilst on the nicotine gum and this made it very difficult to sleep. Sleep deprivation as a side effect can also cause a multitude of health problems in the future, which is why some people use vape oil pens to help them sleep.

Addiction and Long-Term Use

The issue with nicotine is that it is incredibly addictive, and though supermarkets leave a warning on the product to not use for more than 12 weeks, some people become dependent on them for years. ‘I also personally know people who have used the product for years and have experienced stomach problems, high blood pressure, borderline glaucoma, and hair loss, says a 67-year-old wife and mother. All these complications disappeared when they stopped using the gum.

She had been smoking for over thirty years and only managed to quit with the help of the nicotine patch and gum.

I have now been smoke-free for a decade, but not gum-free. It took me years more to get over that addiction, and my experience is far from unique.’

Her personal struggle with fighting the addiction made it very difficult for her to come off of the nicotine replacement therapy. Compared to the nicotine patch (which we do recommend), the gum seemed to take a much larger toll on her health:

I threw out all my cigarettes one night and slapped the patch on. After four weeks on the patch, I decided to use nicotine gums instead, figuring that I would taper off even more on the gum till I was using no nicotine replacement at all.
It didn’t happen. Like any addict, I stopped counting how many pieces of gum I chewed. I kept buying my supply and ignoring the fact that it was taking more and more of the substance to satisfy me. I got so bad that I liked the taste and looked forward to my lozenges the way I had once enjoyed cigarettes. I told myself that it was OK to keep using my lozenges and gum because at least I wasn’t smoking.’

Various Other Health Problems

Nicotine gum also causes various other health issues that develop after long-term use.

‘I’ve been on the gum for about three years, after quitting smoking 20 years ago. My left eye has gotten worse and worse in the last few years and has resulted in my getting glasses and I’ve had four teeth pulled. I use up to 20 pieces of gum per day.’

says a 44-year-old musician.

These health problems may not be connected to the gum, though most seem to appear once the gum is used as a long-term therapy.

Chewing this product can also cause complications on your skin and make it very uncomfortable and unattractive. A 58-year-old software engineer claims that a year ago he quit smoking and relied on gum instead:

‘My face had become horribly dry during the last year. At various times I would get pimples on my face which would leave scars – I now have 11. I now have reddish skin with white dots upon the rash.’

After visiting three different dermatologists, they could not determine what was causing such an outbreak.
Other lesser considered side effects are nicotine withdrawal when you stop using the gum. Symptoms include:
  • Anxiety
  • Headaches
  • Irritability
  • Weight gain

Dental Health

“I formed a habit and could not stop. At times I was chewing 15 to 20 pieces a day. This made the enamel on my teeth wear away and caused indigestion. Never again.”

High Blood Sugar

Some diabetic patients who quit smoking because of its destructive effects, which aggravate the effects of diabetes, were put on NRT. For some time, that apparently helped; however, many people have complained of a rise in blood sugar levels with the consistent use of nicotine gum.

A 38-year-old veteran, who is also a diabetic patient, sent us an email with his concerns about nicotine gums,

“I have presented compliance with my diabetes treatment; however, my FBS is constantly rising. Should I quit using nicotine gum as well? Because this is the only way I can help, restore better health.”

Nicotine causes blood sugar levels to fluctuate. High blood sugar increases the risk of type two diabetes. Conversely, low blood sugar can result in low glucose levels resulting in hypoglycemia. Quitting can reduce the risks of developing these diseases.


The human body has nicotine receptors that act on nerves and muscle fibers, their main effect on the brain is excitation. In this way, nicotine excites the brain, and when such stimulation is continuous, the brain cells start firing up abnormally.

“I have become irritable, and I have started having panic attacks recently. When I was informed by my doctor that I was developing a lung infection, I switched from cigarettes to gums. Since then, I have been unable to concentrate on my work, and it has affected my memory as well,” says a 40-year-old journalist in one of his articles.

Nicotine Gum and Hair Loss

This side effect has started giving anxiety attacks to ladies all over the world.

“My hair was gorgeous and thick before, even when I was smoking, yet ever since I have started chewing nicotine, my hair fall has increased ten times than usual. I am anxious that I will go bald if I don’t stop using the gum. Can anyone suggest me some better alternatives than nicotine gums.” says a 31-year-old model in a TV interview.

“I used the gum for 12 weeks and successfully quit. But I gained weight and lost hair. I had to change some aspects of my lifestyle to lose weight, but the hair ain’t coming back.”

Nic gum is an effective Nicotine Replacement Therapy, but it is not meant to be a long-term solution. It is best to try to wean off of nicotine so as to stop using the gum after 12 weeks from your quit day.

Not everyone will suffer these effects, however. But to avoid this happening, be sure to follow the instructions on the box and take them under a doctor’s supervision.

Benefits of Nicotine Gum

The main benefit of nicotine gum is quitting smoking or other nicotine products. Smoking is one of the significant causes of cancer, heart disease, circulatory disorders, and other illnesses. Also, as mentioned above, nicotine by itself can be harmful.

Many people who badly want to quit try doing so cold turkey. However, this method is not effective for most people.

Nicotine gum replaces nicotine from tobacco and vapes, and the user is gradually weaned off of it until he or she is no longer addicted.

Using the gum under the supervision of a doctor and assistance from a counselor, friends, and family significantly increases one’s chances of quitting.

What Does Nicotine Gum Do to Your Body?

Poor reactions to nicotine gum could be increased heart rate, dry mouth, and throat irritation. However, these side effects usually do not last. As the smoking cessation program progresses, less nicotine is consumed, which will result in a decreased heart rate. Also, feelings like anxiety that can increase one’s heart rate are less likely to occur.

Addiction to Nicotine Gum in Non-Smokers

One of the negative consequences of using gum is becoming addicted to the gum. For this reason, it is crucial to follow the directions on the packet and take no more or fewer pieces than the instructions state.

Most smoking cessation programs involving gum are 12 weeks long. Be sure to discontinue use after 12 weeks.

Nicotine Patches vs Nicotine Gum

It might be possible to take both.
The National Institute for Health Research found that gums and lozenges can be effective when combined with patches. Using both increases the success rate by as much as 25 percent compared with just using one.

Tips on When to Contact the Doctor

It is essential to contact a doctor if you think the side effects are too much to handle or are life-threatening. Also, contact a dentist if you experience periodontal pain, receding gum lines, or anything else that is abnormal.

Finally, patients should contact their doctors if they are still experiencing cravings after completing the smoking cessation program.

Frequently Asked Questions About Nicotine Gum Side Effects

Can Chewing Nicotine Gum Be Harmful?

Short-term usage is not harmful in most cases; however, it can be dangerous if accidentally swallowed by a child or pet. Call an emergency room or veterinary clinic immediately if a child or pet eats nicotine gums.

Does Nicotine Gum Affect the Skin?

Nicotine is known to make wounds take longer to heal, which increases the likelihood of scarring. It can also cause dryness and blemishes, resulting in increased aging.
There are several gum side effects when used over a long period. The most serious are elevated blood pressure, irregular heartbeat, constricted blood vessels, insulin resistance, and gastrointestinal issues. Other side effects are hair loss and skin irritation. Hair loss side effects caused by nicotine may be reversible.

Is Nicotine Gums Bad for Your Lungs?

Nic gum does not expose the lungs to smoke, tar, and other substances found in cigarettes. Therefore, it is highly unlikely to influence lung health negatively.

Does Nicotine Gums Hurt Your Heart?

The long-term nicotine gum side effects earlier mentioned can indicate heart trouble or result in it later on. These side effects are high blood pressure, insulin resistance, and irregular heartbeat.

Can Nicotine Gum Give You Anxiety?

Research has shown that nicotine has anti-anxiety and depression side effects. However, this research has also shown that more nicotine is needed to maintain its anti-anxiety and depression effects as dependency increases.

Does Nicotine Gum Affect Circulation?

Nicotine is associated with several cardiovascular disorders; however, it is difficult to tell how many are caused by nicotine versus how many are caused by other substances found in cigarettes. However, high blood pressure constricted blood vessels, and an irregular heartbeat is a sign of circulatory problems.

Can Nicotine Gum Damage Your Liver?

There is no indication that nicotine can damage the liver.

Does Nicotine Gum Rot Your Teeth?

Using it long-term has been associated with periodontal disorders and side effects because it restricts the mouth’s blood vessels and increases the risk of gingivitis.

Does Nicotine Gum Cause Bad Dreams?

Some users have reported having bad dreams due to smoking cessation therapy. However, it is difficult to tell if this is a side effect of quitting smoking or gums.

Wrapping Up

It’s not just your hair that can fall out. Nicotine gum can also damage your dental health over the long term. From TMJ from chewing too often to the weakening of the mucous membrane that lines the mouth, there are side effects from long-term use.

Nicotine gums may seem like an easy and simple way of quitting smoking, and it’s definitely the most popular “nicotine replacement” product on the market.

But we urge you to look at the side effects and horror stories and think before trying the gum. but there are other options that you can use which are arguably healthier. We particularly like nicotine patches and electronic cigarettes because of their lack of side effects and promising potential.

Published: August 20, 2017Updated: April 4, 2022

James Bickford

My way of understanding the significance of vaping came not only through the disruption of smoking but its effects on society as a whole. Now I bring people to vaping and bring vaping to people. I love using new gear, writing in-depth reviews and generally nerding out about vaping to like-minded people.


Leave a comment

38 comments on “Nicotine Gum Side Effects: Stories From Long Term Users

  • Mark David

    February 28, 2023 at 1:43 am

    The Covid vax contains the venom of 26 different snakes and 10 sea shell animals. mostly poisonous snails. I did not and will not take any vaccine shot, In fact, I haven’t had a vaxx shot of any kind in 32 years (1991). These venoms attack through the Nicotine/Acetylcholine receptors in your body, especially those in the brain. Smoking, or taking a Nicotine supplement (patches, gum, etc.) greatly REDUCE the damage done by the venom-containing vaxxes because they BLOCK the Nicotine/Acetylcholine receptors from these venoms.. I haven’t smoked or used any nicotine or tobacco since 1979, but I recently started chewing one piece of 2mg Nicotine gum per day as a protective shield against being infected by a person that has taken one or more Vaxx shots.

  • Gina

    September 21, 2022 at 10:44 pm

    I have been chewing nicotine gum for over 20 years. The last couple of years I have had side effects and decided to look at the nicotine gum. Yes I chew way to much my blood pressure is off the charts and I am on medicine for it. I have achy bones and a horrible metal taste in my mouth. The metal taste started about six months ago. The horrible vivid dreams are there too. Also irritability is extreme. The majority of these comments are very similar. I have not read anything about the taste of metal so far. I am willing to decrease and quit the nicotine gum. I chew at least 20 pieces a day 2x4mgs. at a time. Something has to change. The best those who are trying to quit the gum.

  • Trish

    March 21, 2022 at 9:55 am

    After quitting smoking 5 yrs and 7 months ago, I started Nicorette gum. I had been on nicorette gum ever since. And not the recommended way. Way more than I should have been. December 2021 came and i had horrid heartburn. I was miserable and had acid reflux. Than i continued to have pain across my shoulder blades and continuous heartburn. It finally eased after a week or two on prilosec. Than beginning of February horrible heartburn came back again. That was it, NO MORE! I went in to get on the patch, anything to get off the gum! The patch lasted 2 days and I haven’t been on nicorette gum since. But my anxiety and irritability the last week has been so hard and stressful. Nicotine is not worth the pain it causes families. Please if you are reading this, and it’s not too late. Stop the gum now.

  • Elizabeth

    September 17, 2021 at 1:14 pm

    I have not smoked for the past 35 years tried a pod under my lips on my gum when the hot sensation went I became really dissy and wobbly that I had to lye down and I slept for hours after it ,how can you explain it .thank you

  • Keith

    September 12, 2021 at 12:06 pm

    Not very useful w/o the dosages involved. Did these things happen with a single piece of 2mg Nicorette? Or after 8 4mg pieces? After a single day or after weeks of constant use.

    Such details matter in determining how risky the stuff is.

  • Neil Wilson

    July 30, 2021 at 7:39 am

    This was very helpful. My wife is 55 and has been chewing the gum for about 8 years. Unfortunately she is going through the menopause and believes all her problems are due to this and not the gum.

  • Charles Marchesani

    June 15, 2021 at 6:33 am

    Hi, my name is Charles, i chewed Nicorette gum for close to 3 yrs. I did not feel any side effects until about the last year of chewing the gum, then i noticed that my mouth would get so dry it felt like it was stuffed with cotton, when i went somewhere i had to make sure i had something to drink and or enough gum so my mouth would moisten. Its been over a year since i quit chewing the gum and i constantly get cotton mouth??

  • Jeff

    January 20, 2021 at 3:45 pm

    Been chewing Nicotine Gum since 1999 and it’s now 2021.. Whew! Seems dental issues (fillings falling out, cracked teeth, cavities) were the only long term side effect associated with it’s use?

  • Steve Barker

    August 13, 2020 at 7:22 am

    Vaping is not side effect free. I vaped when they first came out for about 2 years. Is started getting terrible indigestion (which I had never had before) and shortness of breath. When I tried to fully expel the air in my lungs I would start coughing. Within in a month of quitting the ecigs both of these side effects were gone. You’re breathing water vapor into your lungs that could be full of bacteria, it cannot be good for you. I believe in the years to come when there is more data they will find that vaping is more detrimental to your health then folks think.

  • Bridget Adams

    July 23, 2020 at 1:00 pm

    I think it’s the Aspartame/Nicotine combo and pretty much all these gums have them. I have had seizures, since I tried to stop the first time. I quit cigarettes 20 years ago. I have also lost 4 teeth, had fillings fall out, got rosacea, can’t combine it with alcohol and boredom during a Pandemic. I can’t concentrate and I used too. I “smoke occasionally to try and get off the gum”, usually sleep with it at night. It is very addictive and expensive and dangerous and hard to quit. I am a 67 year old female working at home.

  • Ed

    March 27, 2020 at 2:15 am

    This whole article reads like total fake news. I’ve been using nicotine gum for years and never had any of those side effects. Regardless, it’s bad to be dependent on any stimulant in general for various other reasonsm, but this article seems bogus.

  • Jd

    March 8, 2020 at 12:44 am

    There is not a bit of scientific evidence to support a single word of this article. It reads like a series of imaginary conversations. You reference an article written by a journalist, but won’t identify the journalist or cite the article. Because this is completely made up.


    February 28, 2020 at 8:16 am

    i used to smoke 40 to 50 cigarette a day then i came to know about nicotex gum which i am using from 2 years now and i am facing lot of oral dental and stomach problems till now ididnt knew it was because of gums but after reading the blog i felt like this gums is more addictive then cigarette

  • David

    February 15, 2020 at 3:17 am

    I chewed Nucor

  • Jason

    September 27, 2019 at 10:25 pm

    I’m 30, and i’ve smoked 2 packs a day for nearly 13 years. I’ve been using Nicotine gum since a month now. I only chew 3-4 pieces a day of 4mg gum. And use regular sugar-free gum, to help with those sudden nasty cravings.
    I absolutely don’t feel addicted to the gum at all. Sometimes I happen to skip a dose, but it’s much more easier to get away with it than reaching out for a smoke. The problem with addiction to the gum, in my opinion, is that people consume it way too much. And forget that they shouldn’t chew it like it was regular gum or a candy. It is a medication, to help you cutting down, and eventually get rid off of smoking and, eventually, nicotine altogether. And you should treat it as such.
    My advice to those who find it hard to quit the gum addiction is this: get busy. Get out, have a good long walk, exercise, find a hobby that will keep you distracted. And drink plenty of water.
    Stay safe, please.

  • Supriyo

    September 20, 2019 at 9:26 am

    Is there a way to know how many gums per day were being consumed by all the people mentioned in the article? The side effects mentioned are of course really bad, but if someone is taking, say 20 everyday, that’s a bit extreme. It’s similar to “Sugar causing obesity” Of course if you consume too much of anything, it’s going to be harmful. So what is the safe amount? Is 1 gum a day okay? I’ve been using it for about a week(as an alternative to caffeine, I wasn’t addicted to smoking) I don’t use it everyday, only when I really need to ward off sleep, and even then it doesn’t go beyond 2 in a single day.

  • bryan green

    August 7, 2019 at 6:17 am

    it was informative but I agree vaping is not safe and I can say that because ive done it for several months and can feel my breathing getting worse. its not nearly as bad on the lungs as cigarettes but its bad trust me

  • Nick C

    April 25, 2019 at 2:52 pm

    I quit smoking in August 2015 but it took a furthur 3 years before I managed to get off nicotine lozenges…I was sucking two 4mg at once all day then I got it down to one at a time…then one day in November 2018 I decided to quit them after gum and teeth issues…it was very tough coming off them I had disassociation and sleep issues…the one side effect I can say has definently got better is hair loss…there used to be hair all over my computer desk where it was coming out now that has stopped….

  • Marlene

    August 30, 2018 at 4:55 pm

    Just had to quit the gum after 20 yrs of being addicted to the gum. I have sores on the inside of both cheeks. The biopsy showed buffalo oral mucosa. Not am treating with steroid. Please stop if you cand . What I have could go into cancer

  • A.

    August 8, 2018 at 7:34 pm

    I’ve been using Nicoette gum every now and then when I tried to quit smoking, and when I try to reduce my smoking intake.. VERY ADDICTIVE. At some times I used to pop up a gum after smoking because the nicotine hit from the gum was stronger than smoking..
    Anyway it caused me stomach problems and I have to see a doctor and took antibiotics and then decided to throw the gum and continue smoking!!

  • punit

    May 28, 2018 at 1:59 pm

    I have been using nicotex for over like 4 yrs…its difficult to explain…but believe me all the above reviews are true..rigjt loss to gum and teeth oroblems

  • Gwyn

    May 1, 2018 at 4:18 am

    Hello…My name is Gwyn…and I am a nicotine gum addict…(there should be a 12 step program, for real. I have chewed nic gum for 2 years now. I have become a pro at peeling the little corner back to get to my nicotine treat. The side effect I have experienced is horrible dental problems…(in the process of getting dentures at this time, actually.

    • Ann

      August 29, 2018 at 9:36 am

      I chewed the gum for years then developed terrible dental problems. I switched to lozengers and now I’m facing loss teeth and implants. Has anyone else had this problem.

    • Todd

      March 13, 2019 at 3:56 pm

      Lol – “I have become a pro at peeling the little corner back to get to my nicotine treat. ” I chewed for 9 years after quitting cigarettes. I have around 3 years off the gum. I found this page because I was craving one. Thank you all for the encouragement!

  • Thomas

    April 15, 2018 at 9:20 pm

    I’ve been addicted to nicotine gum for 25 years I usually chew 3 4mg pieces at a time and I chew all day long. I just went cold turkey and quit 6 days ago. It is brutal. I haven’t had any of the side effects that people posted. Costco has the best deal as far as pieces, money ratio. Will keep you posted on my progress

    • R.Edwards

      April 28, 2018 at 2:32 pm

      Please let me know how it goes? Been on 4mg since 2010

  • Pam Keeling

    December 29, 2017 at 12:08 am

    I have been addicted to nigotett gum since 2003. Very addicted. I have had dental issues. Tremors. Muscle weakness. I would tell anyone if you want to stop smoking your better off to go cold turkey. The gum addiction to me is worse than cigarette addiction. I pray one day I will throw this gum out the door. Easier said than done.

  • Ellen

    December 13, 2017 at 7:06 pm

    My mom has developed horrid issues on the skin of her arms, has terrible headaches, and is constantly sick on her stomach. What are your comments about headaches and the gum?

  • Beverly Reed

    December 8, 2017 at 3:59 pm

    Can use of Nicorette gum cause hair loss?

    Can Nicorette gum cause high hemoglobin blood results?

  • anneke andrew

    December 2, 2017 at 4:49 am

    have just read all above stories and I am starting to feel exactly as other people. I am now in my late sixties and very active , healthy and I look very good. I have been taking nicorettes 2mg for at least 10 years now and just cannot get off it. I panicked when once there was no stock in the stores. I am getting trembles, especially in the middle of the night. I wake up at 2.00 am, get my gum, read a book, because I am wide awake. My biggest issue is the trembling and not sleeping and I start to believe that it is caused by Nicorette. I tried normal gums, but it has no effect and will follow with a Nicorette. It really worries me and have now decided to stop if I can. If there is any advise out there, I would appreciate that.

  • Shayne

    November 29, 2017 at 6:08 pm

    I’ve quit several times. This time it going to work lol. I chew nicotine gum. I recommend it. However there are things you should know. Nicotine is a stimulant to your digestive system. Chewing nicotine gum like a cow can cause diarrhea and stomach cramps. The gum is intended to be chewed a few times then parked in your mouth. Then chew again. Chewing nicotine gum like normal gum dis not recommended. The juices from the gum will cause stomach discomforts if you don’t follow the recommended procedures.
    I have never heard not have I experienced nightmares from nicotine gum.
    I started out chewing 4mg tablets and then I’ve dropped to 2mg tablets. My physician said that nicotine gum isn’t the best thing in the world to be chewing ;However it’s far better then smoking.

    • Jesse

      September 11, 2018 at 6:03 am

      Any nicotine being absorbed constantly can cause vivid dreams and or horrible nightmares that you feel as if you are there. These are people who sleeo with the gum in which i have done before. Or forgot the oatch was on… those dreams are way more vivid. Its a trip i had to stop the patch all together because.of the nightmares.

  • Christine Senger

    November 26, 2017 at 1:50 pm

    My husband chewed the nicotine gum for years and chewed more than he should have per day. Now that he has stopped, it’s been about a month and he is so achy all over he can hardly sleep… not sure what he should do about it. Wonderoif loading up on vitamins can help him. He’s 66 years old!

  • R. Birch

    November 21, 2017 at 2:13 am

    I am addicted to nicotine gum. Of course I wish I wasn’t but I think that the warnings regards their use are a little over the top. I’m 75 and have used it regularly for 7 years and do not recognize having any of the side effects you read about.

  • Mike

    November 5, 2017 at 8:05 pm

    This is like trump science, my neighbor’s daughter’s boyfriend’s aunt said that nicotine gum gave her herpes so you should put completely non fda approved chemicals into your lungs.
    I think it’s pretty clear that vaping is safer than smoking cigarettes. Maybe they are correct that nicotine gum has adverse consequences such as described but when offering evidence to support an argument could you please use verifiable sources instead of random unprovable anecdotes?

    • Jesse

      September 11, 2018 at 5:59 am

      You lost me at “trump science”

    • Ben

      May 1, 2019 at 4:36 pm

      I’m pretty sure Trump never said that. You must be a Fake News viewer.

  • Nicky

    November 4, 2017 at 9:17 am

    I agree, Nicorette Gum is addictive. I have been using the gum for 12 months now and I am finding it incredibly difficult to give up.
    I don’t however believe for one second that electronic cigarettes are healthier for you. For starters, they are not regulated and there is no evidence to say they are safe. Who knows what is in these little bottles of liquid vape you can buy at pound shops. E Cig shops constantly open up then vanish without a trace. Furthermore, I know people who use E Cigs and have been using them for 2 plus years. I don’t believe any nicotine replacement used for a long period of time is safe.