DermaFeet Medical Fungi Varnish is a product indicated in cases of onychomycosis or also called nail fungus. It works by helping to eliminate and prevent the proliferation of nail fungus. It works by helping to eliminate and prevent the proliferation of nail fungus. - Indications: DermaFeet Medical Fungi Varnish is a product indicated in cases of onychomycosis or also called nail fungus. It works by helping to eliminate and prevent the proliferation of nail fungus. For use by those over 16 years of age.