Medical centrifuges are machines that rapidly spin fluids to separate substances of different densities by using centrifugal force to produce a form of artificial gravity. According to some companies that make centrifuges, the most commonly used medical centrifuge is a bench-top ultracentrifuge. The ultracentrifuge is widely used in the study of polymers, proteins, nucleic acids, viruses, and other organic macromolecules. Ultracentrifuges are used in biological and chemical laboratories and in medicine to prepare serums and plasma from blood.

The ultracentrifuge is balanced on a cushion of air and spins because a jet of compressed air touches the outer surface. An ultracentrifuge consists of a rotor, cell, drive mechanism, and temperature control. These parts are designed to achieve high centrifugal accelerations. A rotor of a typical ultracentrifuge is eighteen centimeters in diameter and carries ten ounces of liquid in a centrifugal field. The rotor spins in air or another type of gas at atmospheric pressure. The friction between the gas and the spinning of the rotor increases rapidly causing the power needed to drive the rotor to increase rapidly. This increase causes the temperature of the rotor to rise. This is where the temperature control device comes in. If the temperature rises too much it can cause the substance in the tube to remix and disturb sedimentation. Temperature control allows ultracentrifuges to have high rotational speeds. Below are the most common centrifuges found on the market.