Drug allergy is an important and increasing problem in everyday practice. It is estimated that about 15% of adverse side effects of drugs are of allergic nature. This kind of adverse reactions appear where antibodies or activated T cells are directed against drugs. The pathomechanism and symptoms of drug allergy may be connected with every of 4 types of hypersensitivity according to Gell and Coombs. Most frequently, drug allergy manifests as different forms of skin reactions. Some of them like urticaria and angioedema are IgE-related and appear rapidly after drug intake. Others appear as delayed-type reactions and manifest as maculopapular, pustular or bullous exanthema. The diagnosis of drug-induced skin allergy is based on history, clinical picture, in vitro laboratory tests and skin tests (prick, intradermal and patch). The treatment includes drug withdrawal and symptomatic pharmacotherapy.