Bay leaves are an excellent source of vitamin A and vitamin C. The leaves are also high in folic acid, niacin, pyridoxine, pantothenic acid, and riboflavin. Trace amounts of minerals, including copper, potassium, calcium, manganese, iron, selenium, zinc, and magnesium, can also be found in the leaves. The leaves are high in the essential oils cineol and eugenol, giving the leaves their eucalyptus and menthol aroma. The high levels of these oils within the leaves have led to their use to soothe stomach ulcers, relieve gas and colic, and soothe the throat and cough.