BACKGROUND AND OBJECTIVE: We compared the dose requirement and side effect profile of total intravenous anaesthesia using Diprivan to generic propofol at a specific anaesthetic target level utilizing the bispectral index monitor to determine efficacy differences between the two products. METHODS: Sixty women undergoing abdominal hysterectomy were induced with propofol 2 mg kg-1 and maintained with infusion (20-200 microg kg-1 min-1) adjusted to maintain a bispectral index of 50-65. Plasma propofol concentration was measured at 1 and 2 h post induction in 25 patients. RESULTS: Mean (SD) drug doses adjusted for weight and time were similar in the Diprivan and generic propofol groups: 90 (30) microg kg-1 min-1 vs. 90 (20) microg kg-1 min-1 respectively. Mean (SD) plasma propofol levels at 1 and 2 h were also similar (3.0 (1.0) microg mL-1 vs. 3.6 (1.4) microg mL-1, P = 0.2 and 3.0 (1.9) microg mL-1 vs. 3.4 (1.6) microg mL-1, P = 0.58). CONCLUSIONS: Diprivan and generic propofol have similar efficacy at a specified, bispectral index-defined, depth of anaesthesia.