When a patient developed small bowel perforation 10 days after laparoscopic sterilization thermal injury from direct contact with the hot Fallopian tube closely following diathermy was suggested. To test the idea experiments were performed on puerperal patients undergoing laparotomy sterilization (7) patients undergoing laparoscopic sterilization (5) and patients undergoing abdominal hysterectomy (2). Surface temperature changes of the Fallopian tube were recorded continuously before during and after diathermy coagulation with a thermocouple of low thermal capacity placed against the tube and attached to an electronic thermometer data being registered on a U.V. recorder. The point of diathermy rises to a high tubal temperature (frequently over 100 degrees C) but cools rapidly to 56 degrees C the temperature of hot abdominal packs used in surgery and known to cause no thermal visceral injury. Only trivial damage occurred when parietal peritoneum and appendix wall were held against the hot tube until 56 degrees and for 2 minutes respectively. The original suggestion is thus thought unlikely.