Bactericidal penicillins should not be given in association with bacteriostatic antibiotics. On concurrent administration of antiphlogistics, antirheumatics and antipyretics one should bear in mind the competitive inhibition of excretion. Owing to the virtual atoxicity of penicillin. It is not necessary to reduce the dosage in renal insufficiency. Under certain circumstances penicillin can stimulate glycosuria when performing diagnostic blood sugar determinations. The physician should be consulted if side-effects occur.