Green (Phaseolus vulgaris) and yellow beans, also known as snap beans are believed to be native to Central or South America and there are over 150 varieties cultivated today. All beans are members of the Fabaceae (Pea) Family and relatives of peanuts. The genus name, Phaseolus, means "small boat" in reference to its appearance. One of the main differences between string beans and those such as garbanzos and lentils, is that these are picked while young and the entire beans and its enclosure are consumed. In the late 1800's, plant scientists worked at hybridizing string beans, so they no longer had a "string" on their side, which detracted from their appeal. The heirloom varieties still have strings, and many find they are more flavorful, yet require a bit more work to prepare.
String beans are considered a spleen, kidney and yin tonic. They have traditionally been used to improve acne, diabetes, diarrhea, leucorrhoea, night sweats, thirst, and frequent urination. They nourish the pancreas and increase the fluids, or yin aspect of the body. They help in eliminating uric acid, and are thus in relieving the inflammation of arthritis and gout.
Snap beans are very alkaline and the green beans more nutritious than the yellow ones. They are neutral in temperature and sweet in flavor. They are rich in beta-carotene, B complex, calcium and potassium.
Good quality beans have a bright color and snap easily when broken. Look for beans with immature seeds. Young beans with enough fuzz to cling to one's shirt are an indication of tenderness. Large swollen seeds in string beans will foretell a tough bean.
Use string beans in salad, for dipping, to add crispness to other vegetable dishes, soups, as well as in vegetable juices.
A wash made from the tea of young green beans has been used topically to treat acne, cold sores, eczema, and herpes.