Abstract: The presence of phytochemicals cannot be separated from medicinal plants, this is because they are active compounds that makes them performs pharmacological or therapeutic activities in the body of animals. These compounds includes, flavonoids, phenols, tannins, terpenoids, alkaloids and saponins which has anti-inflammatory, antioxidant, anti-helminthic, anti-diabetic, anti-cancer, antifungal, antiviral, cytotoxic, immune-stimulatory properties amongst others. Phytochemicals are natural compounds, chemical free, non-toxic, effective and eco-friendly. Their concentrations in plants can be influenced by the age of plant, specie, geographical location, processing methods and parts of plants used. However, it is wrong to assume that dietary supplementation of medicinal plants cannot be harmful to animals especially when administered above the optimum level. Therefore, the essence of this review is to identify some of the medicinal plants that have been used to feed animals and to also identify their optimum levels. This will further help to address the increasing cases of antimicrobial resistance that has become a global threats and will also help to promote poultry production and food safety.