The following is copied from
Why is Accutane® dangerous?
Accutane® has been linked to numerous cases of severe abdominal side effects and gastrointestinal disorders including Inflammatory Bowel Disease (IBD), Ulcerative Colitis and Crohn’s Disease. In some extreme instances, drastic surgical treatment has been required to treat these disorders, including the removal of parts of the colon and rectum.
The adverse effects of taking Accutane® can take up to several years to show up despite the medication remaining in the blood for only four to seven days. They can also range in severity.
Go to the website to read more about this. They have a class action lawsuit going against Hoffman-La Roche Inc.