It is well known that smoking increases both the severity and frequency of flares in people with Crohn's disease. What is not clear is whether that is due to the nicotine or the thousands of other toxins in cigarette smoke. A cursory search only returns studies which show that smoking cigarettes makes Crohn's worse. I can't find any studies on the topic of whether alternative nicotine delivery methods (such as e-cigarettes) makes Crohn's worse, but if anyone can find some then that would form part of an ideal answer.

As a side note, we know that nicotine tends to actually improve symptoms in Ulcerative Colitis, the other form of inflammatory bowel disease. We know in this disease that this is due to the nicotine and not the other toxins in cigarette smoke, because there are plenty of studies (for UC only) that can be easily found linking the use of nicotine patches to an improvement in symptoms.

Further reading:

Role of smoking in inflammatory bowel disease: implications for therapy

Nicotine treatment for ulcerative colitis

Note: Even though I have already accepted an answer for this question, new studies are done all the time and I would be highly interested in and upvote any other answers that are added which contain more studies on this topic.

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    Good question but I'm a little confused. If no studies have been done on alternative delivery methods, how do you know nicotine improves symptoms in UC?
    – Carey Gregory
    Commented Nov 19, 2018 at 5:10
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    I can find plenty of studies on the topic of alternative nicotine delivery methods and UC, but can't find any on alternative delivery methods and Crohn's. I've edited the question to make that a little clearer. If some can be found, that would form part of an ideal answer.
    – F Chopin
    Commented Nov 19, 2018 at 9:11

1 Answer 1


As suggested by one small human study and one study in mice, nicotine might improve Crohn's disease in the colon but aggravate Crohn's disease in the small intestine.

Nicotine Enemas for Active Crohn's Colitis: An Open Pilot Study (Hindawi, 2008)

Thirteen patients with active rectosigmoid Crohn's diseae...were given 6 mg nicotine enemas, each day for 4 weeks... Mean Crohn's disease activity index (CDAI) decreased from 202 to 153—the score was reduced in 6 patients, unchanged in 3, and increased in one. Frequency of bowel movements decreased in 8 patients and the sigmoidoscopy grade was reduced in 7.

In a study in mice (PubMed, 2002) with chemically induced inflammatory bowel disease, nicotine (added into the drinking water) treatment improved inflammation of the colon but aggravated inflammation of the jejunum (a part of small intestine).

This evidence if far too weak to make any conclusions/recommendations but suggests that differences in the nicotine effect might be due to disease location (Effect of smoking on inflammatory bowel disease: Is it disease or organ specific? - PubMed, 2007).

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    I was hoping for stronger evidence but this is interesting nonetheless. I'll be happy to up vote any other answerers that come along with more studies.
    – F Chopin
    Commented Nov 21, 2018 at 10:17
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    I've searched this quite a bit, but I found the same as you - there seems to be no other human studies about nicotine and Crohn's. There are few articles that discuss other toxins in the cigarette smoke, such as dioxins, which can also be more harmful for the small intestine than colon.
    – Jan
    Commented Nov 21, 2018 at 10:22

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