Phase II studies have been conducted to evaluate the efficacy and tolerability of docetaxel in the treatment of patients with advanced non-small cell lung cancer (NSCLC). Docetaxel was administered to patients with stage III and IV NSCLC at a dose of 100 mg/m2 intravenously over 1 h every 3 weeks. Patients included in these four phase II studies had received either no prior chemotherapy (n = 114) or treatment with cisplatin- or carboplatin-containing regimens (n = 57). Major objective response rates were reported in 33-38% of previously untreated evaluable patients and in 21-27% of previously treated evaluable patients. Neutropenia was the most common adverse event. Non-haematological adverse events included hypersensitivity reactions, skin rash, alopecia and fluid retention. Docetaxel demonstrates significant antitumour activity in patients with advanced NSCLC. Further investigations of this agent with corticosteroid premedication, colony-stimulating factors and other agents active in NSCLC are indicated.