Your horse may be beautiful on the outside, but is he healthy on the inside? Zimecterin is the only leading brand that controls bot larvae in the initial oral stage. Controlling larvae at this stage will prevent them from entering your horses stomach, stopping the cycle of internal damage. Damage, that once started, can continue for months. Zimecterin controls both species and all infective stages of bots. So even if your horse is already infected with the gastric stage you can stop further damage with Zimecterin. 1 dose syringe.