To date (5/2/85), systemic leukocyte interferon has been shown to have little or no therapeutic effect on cutaneous warts. On the other hand, leukocyte interferon administered systemically may have a significant adjunctive role to play in management of recurrent laryngeal papillomatosis, but this is difficult to determine in the absence of placebo controlled, double blind studies. Intralesional administration of leukocyte interferon for cutaneous warts is able to eradicate individual warts, but is not practical presently because the responses are delayed and require multiple injections. Further studies are necessary to determine whether clinically practical regimens can be achieved.