Pyrazinamide is an antituberculosis drug synthesized in the 1950s and formerly used only as salvage therapy. Recent developments have elevated it to a central role in tuberculosis chemotherapy as the essential addition to isoniazid and rifampin which makes it possible to successfully complete treatment in six months. This is accomplished with no increase in hepatotoxicity. The only substantial side effect of this drug given at the dosage and for the duration used in these six-month regimens is a polyarthralgia which is only bothersome and not sufficient to warrant interruption of therapy. More rarely, acute gout is produced. The early history and pharmacology of this now first line antituberculosis drug are reviewed herein.