Anecdotal reports suggest that smoking may be beneficial for patients with inflammatory bowel 
disease (IBD) as nicotine may act through inflammatory mediators within the colonic mucosa. 
Furthermore, there is increasing evidence that cytokines play a pathologic role in IBD. Our aim was 
to determine the effects of cigarette smoking on cytokine levels in the colonic mucosa of patients 
with and without IBD. Mucosal biopsies were obtained from 10 patients with Crohn's disease (CD), 10 
with ulcerative colitis (UC), and 10 healthy controls. Five of 10 patients in each of the three 
groups were smokers and five were nonsmokers. Concentrations of interleukin (IL)-1beta, IL-2, IL-6, 
and IL-8 were determined using enzyme-linked immunosorbent assay (ELISA). Cytokine levels of smokers 
were compared with nonsmokers in each group and with controls. Results were analyzed using the 
Mann-Whitney test; significance was set at p<0.05. The concentration of IL-8 was significantly 
higher in healthy controls who smoke compared with nonsmokers and significantly reduced in smokers 
with CD compared with nonsmokers with CD. Moreover, concentrations of IL-1beta and IL-8 were 
significantly reduced in smokers with UC compared with nonsmokers with UC. Smokers had significantly 
elevated levels of IL-8 in the colonic mucosa. Smokers with IBD had a significant reduction in 
cytokine levels; specifically, IL-1beta and IL-8 for patients with UC and IL-8 for patients with CD. 
Further studies are warranted to determine if this reduction in cytokine levels is histologically 
and clinically significant.