Smoking, the oral contraceptive pill, and Crohn's disease.

Both cigarette smoking and the oral contraceptive pill have been implicated as aggravating factors in Crohn's disease. Based upon the recent demonstration of multifocal gastrointestinal infarction in Crohn's disease, a possible pathogenic mechanism for this condition, we propose how smoking and the oral contraceptive pill may potentiate a tendency for focal thrombosis and hence exacerbate the activity of Crohn's disease.