Phytogenic feed additives (PFA’s) are plant-based ingredients that contain a broad range of bioactive properties including antimicrobial, antiviral, anticoccidial, antioxidant and flavoring. Commonly seen PFA’s include whole herbs, spices and their corresponding potent essential oils, flavonoids and oleoresins that make up of bioactive molecules. These bioactive molecules in livestock and companion species are able to control pathogens and improve intestinal health, thereby enhancing nutrient digestibility and growth performance. The PFA bioactive molecules have a wide mode of action, diminishing any chance of antimicrobial resistance. The properties of PFA’s have demonstrated in commercial practice that they are a viable alternative to antibiotic growth promoters.