This is a concentrated Black Elderberry (Sambucus nigra) extract for supporting the immune system, and used for preventing and treating viruses, such as the flu. This syrup is great for kids because it tastes sweet and is generally well-tolerated by most people, young and old. Contains: Elderberries and vegetable glycerine. For prevention, the dose is generally 1 dropperful (~20 drops) 1-3 times/day depending on your exposure and 1 dropperful every 2-3 hours for acute situations where you actually feel like you're getting sick or the virus has already taken hold. Available in 1, 2, and 4 oz sizes.