The analgesic efficacy and tolerance of tramadol, particularly via oral administration, were evaluated in 180 patients (age range 18-69 years), undergoing ambulatory surgery and superselective spinal anaesthesia. The patients were divided into three groups (A, B and C). 40 drops of tramadol were administered to the subjects of group A 30 min before surgery; the same dose was administered to the patients of group B after surgery; no supplementary analgesia was administered to the group C. Intraoperatively, the respiratory and cardiovascular parameters were monitored in each group. Intraoperatively and postoperatively the degree of analgesia was evaluated by using a visual analogue score (VAS) and a four step verbal scale (FSVS). The results showed a significantly superior and prolonged analgesic effect in the groups treated with tramadol, particularly if it was administered before surgery. Furthermore an excellent profile of drug tolerance with no significant side effects, especially respiratory depression, were observed.