An avermectin-based topical formulation is disclosed which is useful for the treatment of pubic lice and body lice. This topical formulation may comprise an effective amount of avermectin, solubilizers, suspending agents, preservatives, non-ionic surfactants, humectants, and water. Also disclosed are methods of using the topical formulations disclosed within this specification to treat pubic lice and body lice infestations, as well as uses in the manufacture of a medicament for treating a lice infestation on a human patient.