This culinary herb is a mainstay ingredient in many cuisines worldwide. The compact plants can be cultivated outdoors in a garden bed or in indoor containers near a sunny window. A favorite companion plant of tomatoes, basil repels tomato hornworms while improving the flavor of the tomato fruits. Medicinally, basil has antibacterial, antiviral, and anti-aging properties. It also is used as a carminative. Holy basil, in particular, contains antioxidants that help prevent illnesses such as heart disease, lung disorders, and kidney stones.