One hundred and fifty albino rats of both sexes, their body weight ranged between 120 - 150 gin, were used in this study and divided into two main groups for acute (70 rats) and short-term chronic toxicity (80 rats). In acute toxicity study the rats received a single dose of (acetaminophen) APAP (500 mg/kg) and silymarin at . three doses (200 - 400 - 800 mg/kg) singly or concomitantly. In short - term chronic toxicity the rats were given 1/10 of LD50 of APAP and the same doses of silymarin as acute toxicity. APAP induced hepatorenal toxicity in the form of very highly-significant increase (P < 0.0005) in both liver and kidney function tests as well as marked histological changes. No significant biochemical and histologies! changes in rats receiving silymarin even with the high dose. Concomitant administration of silymarin with APAP showed very highly significance decrease (P < 0.0005) in APAP induced hepatorena! toxicity. Thus silymarin was considered as a hepatorenal protective agent.