Patients (142) with advanced gastrointestinal (GI) cancers were treated by photodynamic therapy (PDT) from September 1982 to December 1988. Haematoporphyrin derivative (HpD) (5 mg kg-1) was intravenously given 48-72 h prior to PDT. The light source was an argon dye laser emitting at 630 nm. The entire tumour was irradiated with a light dose of 100-250 J cm-2. Fifteen patients (10.6%) showed complete response (CR), 53 (37.3%) showed partial response (PR) and 32 (22.5%) showed mild response (MR). The clinical results show that the estimated energy dose (EED) of 200-250 J cm-2 is appropriate. All patients were treated by PDT and adjuvant chemotherapy showing good results with a follow-up of 1-5 years; 13 out of 15 patients in the CR group are alive (86.7%); 12 patients survived more than 2 years (8.8%).