The known relationship between smoking and Crohn's
People who suffer from Crohn's disease already know about the negative effects of smoking. Smoking and this disease in particular do not function well together. It has been linked with worsening symptoms of this condition. Even secondhand smoke is known to flare symptoms of Crohn's patients. It was also discovered that people who smoke are more likely to develop this disease.
The effects on people with ulcerative colitis, however, are quite different according to the studies.