Abstract: Embodiments herein relate to compositions herein can include one or more of a tomato extract, a rhubarb extract, a garlic extract, a cashew shell composition, and a saponin composition, wherein the composition prevents or reduces methanogenesis in animals. Embodiments herein also relate to compositions including one or more of glycoalkaloids, saponins, anthraquinones, anacardic acid, and allicin and methods for using the same for mitigating methanogenesis in animals. In an embodiment, a composition can include glycoalkaloids, such as ?-tomatine, that can prevent methanogenesis. In an embodiment, a method of processing animal feed is included. In an embodiment, a method of treating an animal to reduce methanogenesis is included. Other embodiments are also included herein.