['Interplay between wound resistance factors and bacterial innoculum determines the risk of surgical infection. Since cautery causes more damage than the scalpel, our hypothesis is that lower numbers of bacteria are required to infect wounds made by electric cautery than to infect wounds made with a scalpel.', 'Abdominal fascia was incised in 375 rats by cold knife, cutting current, or coagulation current. Wounds were innoculated with increasing numbers of bacteria and histologically scored at 7 days for necrosis, inflammation, and abscess.', 'Coagulation current causes more inflammation, necrosis, and abscesses than the scalpel at all bacterial levels. Electric cutting current is intermediate, causing more damage than the scalpel only after contamination reached 10(5). Above this threshold most wounds were infected in all groups.'] Does electric cautery lower the contamination threshold for infection of laparotomies?