Natron was the alkaline salt mixture used to dry the body during ancient Egyptian mummification. Embalmers packed the corpse in natron or covered it with the material so moisture could be removed before wrapping.
Drying was essential because bacteria and natural decay spread rapidly in a moist body. Egyptian embalmers typically treated the body for about seventy days in the classical description, although the full process included several stages before and after the drying period.
Natron was obtained from naturally occurring deposits, especially in arid areas such as the Wadi Natrun. It was not ordinary table salt: it contained naturally occurring sodium salts and had strong desiccating properties.
Natron also had ritual importance. Purification was central to funerary preparation, and the chemical process supported the religious goal of preserving the body for continued existence. Oils, resins, linen, and other materials were used as well, but natron performed the crucial drying function.