The main objective was to scientifically evaluate the possible hepatoprotective activity of polyherbal formulation PN01. In paracetamol induced model wistar albino rats were divided into three groups. Group I animals were fed orally with 1.0 ml/kg/day of normal saline for seven days. Group II and III animals were treated with herbal formulation (200 mg/kg p. o) and Silymarin (50 mg/kg/p. o) respectively for 7 days. On 7th day Paracetamol suspension was given orally at a dose of 750 mg/kg p. o). In Isoniazid induced hepatotoxicity model, animals were divided into four groups (n=6). Group I animals were fed with standard diet. In Group II, animals were treated with INH (54mg/kg p. o). Group III animals were treated with herbal formulation at the dose of (200mg/kg p. o.) and simultaneously received INH (54mg/kg p. o.) once daily for a period of 30 days. Group IV animals were treated with standard drug Silymarin (50mg/kg p. o.) and received INH (54mg/kg p. o.) 1h after administration of standard drug once daily for a period of 30 days. In paracetamol induced hepatotoxicity, silymarin and test treated group showed a significant (p<0.01) decrease in cholesterol level as compared to Isoniazid treated group. Triglyceride level was significantly (p<0.001) increased in Isoniazid treated group as compared to control group. In Isoniazid induced hepatotoxicity triglyceride level was significantly (p<0.001) decreased in silymarin and test treated groups as compared to Isoniazid treated group. The results suggest that polyherbal formulation may have the potential therapeutic value in the treatment of isoniazid and paracetamol induced hepatic damage and some liver diseases.