Malignant tumours (540 cases), including tumours of the lung, oesophagus, cardia, stomach, rectum, bladder, other urinary genital organs, face and mouth, eyes, ear, nose and throat (ENT), head and neck, breast and skin, were treated using photodynamic therapy (PDT) between 1982 and 1985 in Beijing. All of the cases were identified pathologically and the patients received haematoporphyrin derivative (HPD) (5 mg kg-1) intravenously 48-72 h prior to PDT. An argon-pumped dye laser emitting at 630 nm was used for the treatment. The results were as follows: complete response (CR) was obtained in 227 cases (42.1%), partial response (PR) was obtained in 114 cases (21.1%), mild response (MR) was obtained in 120 cases (22.2%) and 79 cases (14.6%) showed no response (NR). The effectiveness of PDT in the different organs was compared. HPD fluorescence was examined in 409 cases of malignant tumours: 344 lesions (84.1%) revealed red fluorescence (positive reaction), 32 gave an equivocal response and 33 gave a negative reaction. Positive fluorescence was seen in all types of malignant tumour in our study. Indications and limitations of PDT for the different organs are discussed and compared.