The leaflets in this section are authored by an experienced pharmacist. Pharmacists are experts in medicines. The medicines in this section include those used for treating diseases that are caused by the immune system or for regulating how the immune system works, for example after a transplant. The immune system is the system which helps fight infection. However, if the system is too active it can harm the body rather than protect it. If you've ever thought "Who shouldn't take azathioprine?", "How do I take my ciclosporin?", "How do I get the most from my tacrolimus treatment?" and "What problems can imiquimod cause?" information leaflets in this section will have answers for you.