It is well known that there are many drugs which induce edema. Drug-induced edema can be divided into three types by the mechanism as follows, 1) sodium overload, 2) renal dysfunction and 3) hyperpermeability of blood vessel. In the category of sodium overload, edema is induced by much fluid replacement and antibiotics which contain large amount of sodium and sodium bicarbonate. As the category of renal dysfunction, NSAIDs, antihypertensive drugs, anticancer drugs and so on induce edema in patients with renal dysfunction. In the category of hyperpermeability of blood vessel, edema is induced by calcium antagonist, insuline and so on. In order to diagnose drug-induced edema early, it is important that we interrupt or reduce the quantity of suspicious drug.