A method of inactivating viruses comprises contacting the virus with a virucidally effective amount of a composition consisting essentially of a C1 to C3 monohydroxy alcohol or a C2 to C4 diol and a sufficient amount of an acid to adjust the pH of the composition to below 4.6. Topical administration of the composition is preferred and is effective in treating lesions associated infections by viruses such as herpes simplex. Nasal deliverable forms are effective in treating symptoms due to viruses that cause the common cold. Pharmaceutical compositions for use in the present method are provided.