One hundred consecutive male patients undergoing elective inguinal herniorrhaphy were randomized to receive general, epidural or local anaesthesia, and the patterns of ventilation were studied before and after operation. General anaesthesia caused more depression of FEV1 and FVC than the other two methods, but no important arterial hypoxia or clinical chest complications ensued. One patients suffered minor staphylococcal wound infection, and one died of massive pulmonary embolism on the eleventh day.