The purpose of this study was to investigate the pharmacokinetics of carbamazepine at steady state, after multiple doses in patients with elevated serum cholesterol levels. Twelve patients participated in the investigation; patients were divided into two groups according to their total serum cholesterol levels. Each patient received multiple doses of carbamazepine 600 mg po once per day. Blood samples were collected and analyzed for carbamazepine by gas-liquid chromatography. The clearance concept was used to describe the pharmacokinetic behavior of carbamazepine in high and low cholesterol patients. The area under the plasma concentration-time curve was determined by the trapezoidal rule method. This value was used to determine the oral dose clearance. In this study, the authors found that the elevated serum cholesterol and elevated total lipids cause a decrease in drug concentration. The significantly higher values of the total body clearance of carbamazepine, obtained in patients with elevated serum cholesterol levels, may have significance in clinical practice.