Azulfidine (generic: sulfasalazine) is a prescription medication used to treat ulcerative colitis (inflammation of the lining of the colon). Azulfidine EN (the delayed-release form) is also approved to treat rheumatoid arthritis.

Azulfidine belongs to a group of drugs called aminosalicylates. It works to relieve the symptoms of ulcerative colitis including diarrhea, rectal bleeding, and stomach pain by stopping the body from producing certain substances that may cause pain or inflammation in the colon. The exact way it works for rheumatoid arthritis is unknown.

This medication comes in regular and delayed-release tablets. It is taken up to 6 times daily in evenly spaced doses throughout the day, with no more than 8 hours between doses. Take Azulfidine after a meal or light snack, with a full glass of water.

Common side effects include diarrhea, headache and loss of appetite.