The key to any good de-worming program is to have a plan and stick to it. One suggestion we would even have is to have a calender in your barn to help you stay on course. It is best to deworm your horses every two months. Though there is disagreement among experts, it is a common practice to rotate the active ingredient used in order to prevent the parasites from growing resistance to a specific chemical. Keep in mind, this means using a different active ingredient, not simply a different brand. Different brands will often contain the same active ingredient under different names and labels. A few common active ingredients to look for are Moxedectin, Praziquantel, Ivermectin, Fenbendazole, Pyrantel Embonate, and Mebendazole. The most common form of de-wormer application is through an oral paste, yet almost all applications are adjusted by weight so please make sure to read all instructions before giving it to your horse. Here are a few of the wormers we carry: