Abstract: Therapies and compositions are described for use in the treatment of a variety of common viral infections such as those of the upper respiratory tract, eye, stomach and intestines, and such viral lesions as cold sores, canker sores and those caused by genital herpes. The effective ingredient in the various therapies and compositions is the compound L-Lysine monohydrochloride (lysine). The crystalline lysine is ground into a fine powder and dispersed in a variety of aqueous media and other carrier systems. A solution in the form of a spray is administered to the nasal membranes, the mouth and throat, and to the lungs. Lozenges are designed to be dissolved in the mouth, both above the tongue and sublingually, and gels and solutions are applied directly to the lesions. Lysine is also administered in the form of drops, chewing gum, suppositories and by enema. In microcrystalline powder form the lysine may be administered directly into the lungs.