It is produced from soybeans fermented with mould, together with water and salt. It has been used as a seasoning in China (and in Asian cuisine in general) for over 2,500 years. It contains a large amount of antioxidants, is good for the prevention of cardiovascular diseases, clears heat, detoxifies, and helps with loss of appetite. It reached Europe sometime in the 17th century, similar to other types of spices. High-quality soy sauce contains no flavourings or flavour enhancers. It is most ideal to use Shoyu, which is made from soybeans, crushed roasted wheat, water, and salt using a fermentation culture. It has a beautiful dark brown flavour and is suitable for seasoning vegetables, soups, and other dishes prepared in the Asian style. Another type of high-quality soy sauce is Tamari. It is darker than Shoyu and is created during the production of miso. Therefore, its flavour is much more pronounced. It is also richer in minerals and trace elements and is saltier. It is also suitable for preparing dishes or sushi.

Excessive consumption may cause phlegm. It has a salty and sweet taste and a cold nature.