Fourteen patients with aggressive juvenile papillomatosis were treated with systemic administration of alpha-type interferon (IFN). This initial dosage of 2 million units alpha-interferon/m2 was modified if a favorable response in the papilloma growth occurred, or if persistent drug-related side effects developed. Half of the patients showed a sustained response while on IFN, and two patients had a complete response. Persistent elevation in SGOT was the main dose-limiting toxicity, especially in infants below age seven years. All side effects subsided after the drug was discontinued. Further studies are recommended.