Milbemycin oxime is a macrocyclic lactone with a broad-spectrum of activity against internal parasites (roundworms) and all development stages of mites. It is ineffective against tapeworms, flukes, fleas, ticks, mosquitoes, flies, and lice.
Milbemycin oxime is sold for use in dogs and cats against heartworm (Dirofilaria spp). However, it is effective against numerous other roundworms, including Baylisascaris procyonis (raccoon roundworm), lungworms (Angiostrongylus vasorum and A. abstrusus) eye-worms ( Thelazia callipaeda).
In birds, milbemycin oxime is used off label for treatment of mites.