Soaking black beans in vinegar is a health preserving method. Black beans are traditional health food. There is also a saying among the people that "if you want to live a long life, you should always eat black beans", and together with Qiongzhen Ganoderma lucidum and Dendrobium candidum, it has become the three treasures of health care.

The book Materia Medica in the Tang Dynasty said that black beans can "improve eyesight and soothe the nerves". Long service time, good color, white but not old. In addition, in the book Compendium of Materia Medica, there are many examples of eating black beans for health preservation, such as "swallowing 27 black beans every morning until you are old", "Peach blossoms are boiled with black beans, and if you eat them often, you can tonify the kidney" and so on. Chinese medicine believes that "beans are the valley of kidney", but according to the theory that five colors enter the five internal organs, black enters the kidney, so eating black beans often will naturally improve the effect of tonifying kidney. We often say that the kidney dominates the bone, while "the tooth is the bone".

Black beans can generally be divided into black-skinned green beans and black-skinned soybeans.

Black-skinned mung bean is named for its dark seed coat and blue kernel. This variety is so precious mainly because it is rich in protein, vitamins, iron and so on. Has high medicinal value. It is a nourishing product of traditional Chinese medicine. According to the theory of traditional Chinese medicine, it has the functions of nourishing yin and benefiting qi, improving eyesight, expelling wind and preventing heat, promoting blood circulation and detoxifying and blackening hair. It can be taken orally or externally, and it is effective when used alone, especially when combined with other drugs. In Compendium of Materia Medica, there are as many as 59 prescriptions that only use black beans as unilateral treatment.

The scope of treatment involves internal medicine, gynecology, surgery, facial features, drug poisoning and so on. , and has a wide range of uses, usually used as a refreshing tonic. Because of this function, green-core black bean is listed as a tight material in the international market and sells well in Hong Kong, Southeast Asia, Japan, South America, Northern Europe and other countries and regions. Black-skinned soybean is a variety introduced from Japan with high nutritional content. It is a good material for making candied fruit, which is deeply loved by Japanese.