Treatment for IBD Related Diarrhoea

Drugs used to treat active IBD

A range of drugs are used to treat IBD and then to help maintain remission once it is under control. If you are on such medication, you should find your diarrhoea lessens as the drugs prescribed for your IBD take effect. 

Some drugs, such as 5 ASAs and steroids, tend to act quickly while others, such as azathioprine and methotrexate, take much longer to work. Some people may get diarrhoea as a side effect of these medications. If you do continue to have a flare up or to experience serious diarrhoea, you may need to change your medication. Talk to your specialist about this. 

Antidiarrhoeal drugs
Antidiarrhoeals work by slowing down the contractions (muscle movements) of the gut, so that the food takes longer to pass through your system. This allows more time for the water to be reabsorbed and for the stools to become firmer and less urgent.


Loperamide (Imodium, Arret) is a commonly used and effective antidiarrhoeal drug. It is long-acting and usually only needs to be taken once or twice a day, although it can be taken more often if needed. Other antidiarrhoeals such as diphenoxylate (Lomotil) and codeine may need to be taken three or four times a day. 


The patient information leaflets that come with antidiarrhoeals such as Loperimide usually advise against  taking them if you have IBD. This is because by stopping the diarrhoea this type of drug can seem to be ‘curing’ a symptom that needs further investigation. Constipation can also sometimes be a side effect of antidiarrhoeals. So, if you have IBD and especially if you are having an acute or severe flare up, do not take any antidiarrhoeal medicines without first checking with your doctor or IBD team.

Antispasmodic drugs
These work by relaxing the intestinal muscles to slow down bowel movements in a way that not only helps to relieve diarrhoea, but also the cramping pain often accompanying diarrhoea. Brands include Buscopan and Colofac. They are usually safe to take, but check with your doctor first. 

Bile salt drugs 
These include cholestyramine (Questran) and colestipol (Colestid) which come in powder or granule form, and a newer drug, colesevalam, which comes as tablets. These drugs absorb the overflow bile salts,  preventing them reaching the colon and causing diarrhoea. They also reduce the absorption of other drugs, so should not be taken within 4 hours of taking other medication. You may be offered the ‘lite’ version of chlorestyramine – this can cause diarrhoea and abdominal pains, so ask for the normal version. 


Bulking agents 
Bulking agents or ‘bulk formers’ are made from a type of plant fibre (usually ispaghula or sterculia). Popular brands include Fybogel and Isogel. These come as granules which, when taken with plenty of water, swell up inside the bowel, thickening liquid stools or softening hard stools and so providing the bulk needed for the bowel to work normally.


Bulking agents can be useful for both diarrhoea and constipation. They are generally safe for people with IBD, although they may cause bloating and wind, and should be avoided if you have a have a stricture (narrowing) of the bowel, as sometimes happens with Crohn’s Disease.

You can find further information on all these types of drugs in our booklet Drugs used in IBD and our individual drug treatment information sheets.