The effect of tilorone hydrochloride on the growth of several animal viruses in tissue cultures.

Tilorone hydrochloride, at a concentration of 10 mug/ml inhibits the growth of herpes simplex virus type 1 in BS-C-1 cells. The growth of vaccinia virus in BS-C-1 cells is partially inhibited; however, six viruses containing RNA, including four members of the togavirus group grown in chick fibroblasts, are not affected by the drug. The inhibition of the growth of herpes virus by tilorone hydrochloride is greater when the multiplicity of infection is lower than 1 p.f.u/cell and when the drug is added early in the course of infection.