Nowadays, the use of medicinal plants in animal production is increasing due to the widespread concern over possible cross-resistance to antibiotics among many microorganisms, a result of their indiscriminate subtherapeutic use in animals. There is a global trend to limit the use of antibiotics in animal products. The prevention of antibiotic use in poultry diets has led to a reduction in growth performance. Consequently, there is a high demand for natural substances that can achieve similar growth enhancements and positively affect poultry health. Medicinal plant extracts are one of the alternatives that have antimicrobial and growth-promoting effects on poultry. In this book, the benefits of using medicinal plants on different parameters of poultry are discussed.