Green beans are black beans, also called black beans. It is rich in protein, various minerals and trace elements. Traditional Chinese medicine thinks it is sweet, flat and non-toxic. Has the effects of relieving exterior syndrome, clearing away heat, nourishing blood, calming the liver, tonifying kidney, nourishing yin, and tonifying deficiency and black hair. Li Shizhen said: "Black beans have a variety of kidney functions, so they can control water, reduce swelling, reduce qi, treat wind and heat, promote blood circulation and detoxify."