Fifty four patients with squamous cell lung cancer, treated with Cyclophosphamide (750 mg/m2), Adriamycin (50 mg/m2), Vincristine (1.5 mg/m2) and Bleomycin (30 mg) (CAVB) in a 2 day scheduled regime, showed an overall median survival time (MST) of 32 weeks (28 weeks for non-responders and 46.5 weeks for responders--a non-significant difference). The response rate was 24%, the median duration of response being 23 weeks. Bone marrow toxicity was not a major problem. A further 21 patients received the same drugs but in a single bolus (unscheduled regime). Comparison of their results with the 25 patients randomised to the scheduled regime showed no significant difference in MST or toxicity. The addition of Cis-platinum (50 mg/m2) to the unscheduled CAVB regime (CAVBP) in a further 22 patients did not result in an improvement either in survival or response, but added to the toxicity.