As the others have said, it needs reducing very gradually - you must talk to your GP about the exact amount to cut down - or whether in fact you can get off them at all, some people can't. The problem is that your body produces steroid naturally. A feedback mechanism ensures that it doesn't produce too much. When you take steroid tablets, your body realises that there is enough steroid in your bloodstream, and shuts down production. If you suddenly stop taking them, your body won't have a chance to step up production in time and you risk a flareup in whatever problem the steroids were treating. The other reason to talk to your GP is that you may not be aware that things are flaring up - eg blood test results may indicate that things are going wrong before you know about it, so you may have to increase the dose again temporarily.