Quest horse wormer is a specially formulated palatable dewormer gel for horses and ponies. The drug moxidectin is distinctly different from other paste wormers. Effective in the treatment of large and small strongyles, encysted cyathostomes, ascarids, pinworms, hair worms, large mouth stomach worms, and bots. Treats horses up to 1,500 lbs. For horses and ponies 6 months of age or older. Quest for horses is safe for pregnant mares. Moxidectin.