5 mg Ivermectin® per ML. Enters the bloodstream through the skin. Wormer is effective against mature and immature stages of internal and external parasites including roundworms, lungworms, grubs, mange mites, horn flies (for up to 28 days!) and biting and sucking lice. Available in the following sizes: 250 ml, 1 liter, 2.5 liter, 5 liters.