Introduction: In recent years, the consumption of chicken meat in Iran and other countries has grown significantly. With the poultry farming growth, the use of drugs and chemical supplements has increased. they are often associated with undesireable side effects. Medicinal plants with lower costs and fewer side effects can be effective substitute and more acceptable. Therefore, we investigated the effect of medicinal plants and their mechanism in poultry. Search Method: Scientific databases, authentic Persian and Latin articles, and authentic books have been used in this article. Results: We have done a lot of research on medicinal plants, some plants with their properties and mechanisms are described below. Yucca schidigera and Quillaja Saponaria are traditionally used as sources of Saponin. Saponin is a natural detergent or surfactant that is soluble in water and fat. Saponin has anti-protozoal and anti-fungal properties, changes the intestinal mucous membrane, reduces egg cholesterol, and reduces carcass fat. Quillaja Saponin is also used as a carrier in some veterinary vaccines. Also, yucca has polyphenolic compounds with antioxidant activity. Thyme, which is from the mint family, contains ether thymol and carvacrol compounds. Its essential oils have antimicrobial, antifungal, and antioxidant activity. Dill is from the parsley family, which has antimicrobial properties, reduces blood fat and cholesterol, and has antioxidant properties. Therefore, these drugs can be used a lot in the poultry industry. Conclusion: According to the research, it has been found that medicinal plants have many properties, including fighting against viruses, bacteria and fungi. Therefore, considering the cost of preparation and the very low side effects of medicinal plants compared to chemical drugs, we can use these plants more.