Acetone, or propanone, is an organic compound with the formula (CH3)2CO. It is the simplest and smallest ketone. It is a colourless, highly volatile and flammable liquid with a characteristic pungent odour. Acetone is miscible with water and serves as an important organic solvent in its own right, in industry, home, and laboratory. Acetone is produced and disposed of in the human body through normal metabolic processes. It is normally present in blood and urine. People with diabetic ketoacidosis produce it in larger amounts. Acetone is not regarded as a waste product of metabolism. However, its physiological role in biochemical machinery is not clear. A model for the role of acetone metabolism is presented that orders the events occurring in acetonemia in sequence: in diabetic ketosis or starvation, ketone body production (b-hydroxy-butyrate, acetoacetate) provides fuel for vital organs (heart, brain, among others) raising the chance of survival of the metabolic catastrophe. However, when ketone body production exceeds the degrading capacity, the accumulating acetoacetic acid presents a new challenge to the pH regulatory system. Acetone production and its further degradation to C3 fragments fulfill two purposes: the maintenance of pH buffering capacity and provision of fuel for peripheral tissues. Since ketosis develops under serious metabolic circumstances, all the mechanisms that balance or moderate the effects of ketosis enhance the chance for survival. From this point of view, the theory that transportable C3 fragments can serve as additional nutrients is a novel view of acetone metabolism which introduces a new approach to the study of acetone degradation, especially in understanding its physiological function and the interrelationship between liver and peripheral tissues. (PMID 10580530). Acetone is typically derived from acetoacetate through the action of microbial acetoacetate decarboxylases found in gut microflora. In chemistry, acetone is the simplest representative of the ketones. Acetone is a colorless, mobile, flammable liquid readily soluble in water, ethanol, ether, etc., and itself serves as an important solvent. It is an irritant and inhalation may lead to hepatotoxic effects (causing liver damage). Acetone can be found in Clostridium (PMID:685531).