D-lactate is a type of organic acid that is produced during the fermentation of carbohydrates. It is one of the two optical isomers of lactic acid, the other being L-lactate. D-lactate is primarily formed by certain bacteria in the gut and can be found in small amounts in various foods. In the human body, excessive levels of D-lactate can lead to a condition known as D-lactic acidosis, which may occur in individuals with certain metabolic disorders or after consuming large amounts of carbohydrates. Monitoring D-lactate levels can be important for diagnosing and managing these conditions.