This information is for people who have Crohn's disease. It tells you about steroid tablets, a treatment used for a flare-up of Crohn's disease. It is based on the best and most up-to-date research.
Do they work?
Yes. If you're having a flare-up of Crohn's disease, taking steroids can help get rid of your symptoms. However, steroids do have side effects, so you and your doctor will have to weigh up the risks and benefits of treatment.
What are they?
Steroids are drugs that reduce inflammation. Their full name is corticosteroids. They're similar to chemicals your body makes naturally. They're not the same as the anabolic steroids that some bodybuilders use. However, they can still have side effects, especially if you take them for a long time.
Steroids come as tablets. You'll probably need to take them once or twice a day.
There are lots of different steroid drugs. Some examples that have been tested for Crohn's disease are:
Steroids are often used to treat moderate or severe flare-ups of Crohn's disease. For milder attacks of symptoms, your doctor might recommend aminosalicylate drugs instead. However, aminosalicylates don't work as well as steroids. 
How can they help?
Taking steroids for several weeks can get rid of or reduce symptoms of Crohn's disease. Steroids can help with diarrhoea, stomach pain, feeling sick and vomiting. If you've been finding it difficult to eat, steroids can help you get your appetite back. 
One study followed people who took prednisolone for 17 weeks.  After this time, 6 in 10 people had symptoms that had gone away or were much better. Only 3 in 10 people taking a dummy (placebo) treatment got better.
Another study looked at a steroid called methylprednisolone.  After taking it for six weeks, more than 8 in 10 people had no symptoms or were much better. Only 4 in 10 people who took a placebo were better.
In a study looking at budesonide, half the people taking it had improved, compared with a quarter of the people taking a placebo. 
There are lots of steroid drugs, and lots of different doses you might be prescribed. Methylprednisolone and prednisolone seem to work slightly better than budesonide, although they also cause more side effects.  One study found that higher doses of budesonide worked better than lower doses. 
How do they work?
Steroids affect your body in lots of ways, but one of their most important actions is to reduce inflammation. They do this by blocking the production of chemicals in your body that are responsible for causing inflammation.
The symptoms of Crohn's disease happen because you get patches of inflammation on your bowels. So, medicines that reduce inflammation should help to get rid of your symptoms.