A study was conducted to see the effect of 15- and 30-day corticosteroid therapy (prednisolone 0.25 mg/kg/day) on the metabolism of antipyrine and chloramphenicol in rabbits. Antipyrine and chloramphenicol were given to rabbits orally at doses of 20 and 50 mg/kg, respectively on days 0, 15 and 30 of prednisolone therapy. The half-life of antipyrine and chloramphenicol were significantly reduced (p