The effect of central iv hyperalimentation (IVH) as an adjunct to aggressive antineoplastic therapy for small cell carcinoma of the lung was evaluated in a randomized trial with 119 evaluable patients. IVH was given over a 28-day period with higher caloric and protein intake for patients nutritionally depleted on entry in the study; all patients were escalated in caloric and protein intake to maximize nutritional repletion. Combination chemotherapy and radiation therapy induced a 45.5% complete response rate and an overall response rate of 92.8%. Median survival for patients with limited disease was 18 months; median survival for patients with extensive disease was 11 months. Patients randomized to receive IVH did not have a better response rate (P = 0.97) or survival (P = 0.78) than control patients. IVH did not significantly alter the survival for patients who at baseline had greater than 5% pretreatment weight loss, low caloric intake, decreased serum albumin, or reduced total iron-binding capacity. Significantly more febrile episodes were seen in IVH patients than in control patients (P less than 0.001). Short-term IVH to patients with this malignancy who are capable of enteral alimentation cannot be routinely recommended as adjunctive therapy.