Mania can occur by chance association during drug treatment, particularly in patients predisposed to mood disorder. Single case reports are unreliable, and evidence must be sought from large series of treated patients, particularly those with a matched control group. Drugs with a definite propensity to cause manic symptoms include levodopa, corticosteroids and anabolic-androgenic steroids. Antidepressants of the tricyclic and monoamine oxidase inhibitor classes can induce mania in patients with pre-existing bipolar affective disorder. Drugs which are probably capable of inducing mania, but for which the evidence is less scientifically secure, include other dopaminergic anti-Parkinsonian drugs, thyroxine, iproniazid and isoniazid, sympathomimetic drugs, chloroquine, baclofen, alprazolam, captopril, amphetamine and phencyclidine. Other drugs may induce mania rarely and idiosyncratically. Management involves discontinuation or dosage reduction of the suspected drug, if this is medically possible, and treatment of manic symptoms with antipsychotic drugs or lithium.