According to a study from the University of East Anglia performed under the leadership of Dr. Andrew Hart, aspirin use may lead to an increased risk of the development of Crohn's disease. The researchers studied 200,000 volunteers between 30 and 74 years of age.
"Crohn's disease is a serious condition affecting 60,000 people in the UK and 500,000 people in the US. It is characterized by inflammation and swelling of any part of the digestive system. This can lead to debilitating symptoms and requires patients to take life-long medication. Some patients need surgery and some sufferers have an increased risk of bowel cancer."
Past research has shown that aspirin may be harmful to the bowel. Volunteers for the study who regularly took aspirin for a year or longer were found to be more likely to develop Crohn's disease. Aspirin did not seem to affect the risk of developing ulcerative colitis, which has similarities to Crohn's disease.
http://www.medicalnewstoday.com/articles/187549.php