Thai sweet basil leaf is used in large quantities, in whole leaves and sprigs, in many types of dishes, including curries, stir-fried dishes, salads and soups. As with many leafy herbs, this basil can be kept fresh by placing it in a glass with the cut ends in water, covering it with a plastic bag and storing it in the refrigerator. Or you can wrap the herbs in paper towels before bagging them in plastic for refrigerating. They will stay fresh for about a week.