Ninety-nine elective abdominal surgeries were performed under high dose epidural fentanyl anesthesia. PGE1 (0.02 microgram.kg-1.min-1 = 0.02 gamma) was administered to 34 patients (0.02 gamma group), and PGE1 (0.05 gamma) was administered to 16 patients (0.05 gamma group). PGE1 was not administered to 49 patients (control group). The effect of PGE1 on body temperature and on postoperative shivering was compared within three groups. In the 0.02 gamma group, the temperature of the fingertip was significantly higher and the rectum-fingertip temperature gradient was significantly lower than in the other groups. The forearm-fingertip temperature gradient was lower in the 0.02 gamma and 0.05 gamma groups than in the control group. The incidence of postanesthetic shivering was significantly lower in the 0.05 gamma group than in the other groups. These results suggest that; 1) PGE1 (0.02 gamma and 0.05 gamma groups) affects the peripheral blood flow and peripheral temperature, and 2) PGE1 (0.05 gamma group) significantly affects the incidence of postanesthetic shivering.