Teicoplanin is a new antibiotic currently undergoing clinical evaluation. Consecutive patients undergoing elective vascular surgery (n = 28) were randomised to receive a single intravenous bolus of 400 mg teicoplanin 1, 3, 6 or 12 h prior to surgery as prophylaxis against Gram-positive infection. Serum and fat antibiotic levels were measured and found to exceed the established MICs for common staphylococcal and streptococcal infections for at least 12 h following administration. This suggests that teicoplanin would be a useful choice of antibiotic in the prophylaxis and treatment of appropriate infections in elective surgery. By extrapolation, teicoplanin would also be of use in the prophylaxis and treatment of suitable infections seen in traumatised patients.