Supplemental therapy


Antibiotics kill or stop the growth of bacteria, and are sometimes used for IBD.

They have a well-established role in helping to treat complications of Crohn’s Disease such as abscesses and fistulas (abnormal connections between the bowel and the skin or other organs). Antibiotics have also been tried as a treatment for other IBD symptoms, often in conjunction with other drugs. This use is based on the theory that while the exact cause of IBD is still unknown, it seems very likely that it involves an abnormal reaction of the immune system to intestinal bacteria. Antibiotics can reduce these bacteria, and it is also known that some antibiotics may have an immunosuppressant effect.

Most of the evidence suggests that antibiotics are not that effective as a treatment for Crohn’s flare-ups or as maintenance treatment. However, a recent review concluded that the two most commonly used antibiotics, metronidazole and ciprofloxacin, may be helpful for treating active Crohn’s Colitis (Crohn’s in the colon), and after surgery. It also confirmed the effectiveness of antibiotics for abscesses and fistulas, and in helping to treat pouchitis (inflammation of an ileo-anal pouch, a complication that sometimes follows surgery for UC).


This is the most commonly prescribed antibiotic for Crohn’s Disease. It is usually taken as a tablet, but it can be taken as a suppository or be given by injection. Side-effects May include nausea, lack of appetite and a metallic taste in the mouth. More rarely, long term use can cause nerve damage and a tingling in the hands and feet. It is best to avoid drinking alcohol while taking metronidazole and for at least two days following the last dose, as there can be an interaction.


Ciprofloxacin is also used for the treatment of Crohn’s and has been found to be as effective as metronidazole, with fewer side effects. It too is normally taken as a tablet, but can be given by injection. Common side effects include nausea and diarrhea, and it may interact with some of the other medications used for IBD.