Phytochemicals are plant derived products added to the feed in order to improve performance of livestock and poultry. These are used as feed additive to healthy animals under common practical conditions of production of food of animal origin rather than the veterinary use for prophylaxis and therapy of diagnosed health problems.Now we use antimicrobial growth promoters in livestock and poultry feeding. But due to the prohibition of most of growth promoters, plant extracts have gained interest in livestock feeding strategies. The risk of the presence of antibiotic residues in milk and meat and their harmful effects on human health have led to their prohibition for use in livestock feed. Majority of herbal plants are safe and economical. Generally, plant extracts have no problem of drug resistance.