Alloxan, sometimes referred to as alloxan hydrate, is an organic compound with the formula OC(N(H)CO)₂C(OH)₂. It is classified as a derivative of pyrimidine. The anhydrous derivative OC(N(H)CO)₂CO is also known, as well as a dimeric derivative. These are some of the earliest known organic compounds. They exhibit a variety of biological activities.Alloxan is a toxic glucose analogue, which selectively destroys insulin-producing cells in the pancreas (that is, beta cells) when administered to rodents and many other animal species. This causes an insulin-dependent diabetes mellitus (called “alloxan diabetes”) in these animals, with characteristics similar to type 1 diabetes in humans. Alloxan is selectively toxic to insulin-producing pancreatic beta cells because it preferentially accumulates in beta cells through uptake via the GLUT2 glucose transporter. Alloxan, in the presence of intracellular thiols, generates reactive oxygen species (ROS) in a cyclic reaction with its reduction product, dialuric acid. The beta cell toxic action of alloxan is initiated by free radicals formed in this redox reaction. Studies suggests that alloxan does not cause diabetes in humans. Others found a significant difference in alloxan plasma levels in children with and without diabetes Type 1.