5-ASA medications work directly on the bowel lining, where they reduce inflammation. The exact way by which they reduce inflammation is unclear. They are used to treat symptoms of a flare-up and to help keep the condition in remission.

The following 5-ASA (5-aminosalicylic acid) medications are available in Canada to treat Crohn's disease:

5-ASA medications are available as pills, enemas, and suppositories. Each medication has a slightly different formulation that allows it to reach different areas of the bowel.

Side effects may include nausea, vomiting, loss of appetite, diarrhea, abdominal pain, skin rash, or headaches. Serious side effects include bone marrow suppression (which may change blood cell levels and may increase the risk of infection), heart problems (i.e., inflammation of the muscle surrounding the heart), kidney and liver damage, and allergic reactions.

People allergic to sulfa medications should avoid sulfasalazine, and those allergic to ASA should avoid 5-ASA medications.

Your doctor may recommend that you get regular blood tests and checkups while taking 5-ASA.