Law suits of surgeons are increasing in number. Although the surgeon has no obligation concerning results, but only concerning means, the causes of postoperative infections are numerous: inadequate preoperative work-up (chronic focal infection), operative infection by means of an assistant or a visitor, inadequate air conditioning, lengthy operation, prolonged intravenous catheter and viral hepatitis after transfusion are some examples. Liability of the anaesthetist is a difficult problem. In many institutes one anaesthetist simultaneously monitors more than one anaesthesia. The cause-effect relation between the infection and the surgical malpractice must be proven by the patient; this creates an athmosphere of suspicion in the surgical team. More recently the courts have admitted that an infection can render the patient less resistant to another complication, of which he may die.