Plants are excellent source of active components which act as a natural antimicrobial agent and used for treatment of various diseases in whole world from ancient time. As a result the main focus of researchers is on the plants, especially herbs and spices. Tulsi is most sacred plant of the India. It is cultivated for medicinal and religious purposes. Ocimum sanctum has many beneficial properties namely anti-oxidative, antimicrobial, antistress, antidiabetic, antiviral and many others that’s why this plant is also given the term “Queen of Herbs”. Tulsi is one of the most important aromatic herb, which is widely used in Pharmaceutical Industry. O. sanctum is mostly used in the form of extract and oil. The main secondary metabolites ofTulsi extract is Eugenol, Linalool, ?-Caryophyllene, Carvacrol, Apigenin, Rosmarinic Acid, Urosolic Acid, these are derivatives of alkaloids, phenols, glycosides, flavonoids, tannins, saponins, terpenoids, steroids andquinone isolated from Ocimum sanctum and other medicinal plants. Tulsi leaves extract also inhibit the growth of pathogens which is responsible for spoilage of fresh produce. Tulsi extract shows inhibitory effects against pathogens such as Staphylococcus aureus, Pseudomonas aeruginosa, E. coli, Klebsiella pneumonia, Proteus mirabilis, Salmonella typhimurium, Salmonella typhae, Shigelladysentriae, Bacillus pumilus, Aspergillus spp., Candida albican and Penicellium spp. Essential oil and extract of Tulsi leaves have antiviral properties that’s why it is used extensively in medical practices. It is an excellent antimicrobial agent so it is used in food products as an ingredient as well as medicine.