BACKGROUND: This study was conducted to evaluate the effect of propofol on the histamine release during general anesthesia. METHODS: Ten premedicated adult patients, ASA physical status I or II, 20-55 yrs scheduled for elective surgery were included. Venous blood samples (3 ml each) were obtained from median cubital vein before induction as a control and at 1, 3, 5, 10, 30, 60, 120 minutes after the administration of propofol and postoperative one hour to measure the plasma histamine concentrations. After intubation with vecuronium, anesthesia was maintained with propofol in combination with 60% N2O and 40% O2. Mean arterial pressure, heart rate were measured and the development of skin wheal, facial flushing, bronchospasm were monitored. RESULTS: The changes of the serum histamine concentration did not show any significant differences, and hypersensitivity reactions were not observed. Hemodynamic changes at 1, 3 minutes may be due to the effect of propofol on mean arterial pressure and heart rate, so these changes did not correlate with plasma histamine concentration. CONCLUSIONS: Propofol was found to be a useful anesthetic agent without histamine release for patients with allergy or asthma.