In aprospective randomized double‐blind trial using a 1 g single dose of cephamandole versus placebo, given I h before surgery, the wound infection rate after elective surgery for gallbladder stones in 200 consecutive cases was 11%, being 15% in the placebo group and 7% in the cephamandole group (x2= 4.03; P<0.05). The average hospital stay was 7.7 days in the absence of wound infection and 13.6 days in the presence of wound infection. Contaminated bile was significantly positively related to wound infection, and cephamandole significantly protected the culture‐positive group from wound infect