Jeffers Ivermectin Horse Wormer Paste, Single Dose Broad spectrum control - controls 46 species and stages of worms and botsAnthelmintic and boticideKills internal parasitesTreats up to 1250 lb body weight Jeffers Ivermectin aids in the control of:Large and small strongyles, pinworms, hairworms, threadworms, stomach worms, lungworms, and roundworms.