The study was performed in the animal house of college of Science, University of Salahaddin -Erbil. The physiological effects of Rhubarb Root, Lovastatin and their combination on some haematological and biochemical value in male rats (Rattus norvegicus) were studied. Fifteen rats were randomly assigned to 5 groups, (T1) cholesterol diet, (T2) Lovastatin, (T3) Rhubarb (T4) Rhubarb and Lovastatin and (T5) as a control. The results can be summarized as follows:- Serum glucose (s.g) concentration shows significant differences between treatments. (T1) shows significant increment in serum cholesterol (s.ch) as compared with control (T5) Total cholesterol showed a significant differences (T3 and T4) treatments when compares with the control group (T5). To demonstrate the effects of rhubarb Lovastatin and their combination treatments on the haematological parameters, we compared the hematological values of the groups (T2, T3 &T4) were compared to control group (T5) subsequently then we focused on inhibitory effects of combination of Lovastatin and Rhubarb. It was concluded that the rhubarb root was effective in lowering serum cholesterol especially when giving in combination with Lovastatin group