A reduction treatment agent made of a powder with a particle size within a range of 1500 to 3000 mesh, the powder containing: 20 to 40 parts of a mixed-oxide powder containing magnesium oxide and zinc oxide； and 60 to 80 parts of an organic acid powder containing calcium, ascorbic acid, citric acid and salt. The reduction treatment agent may further contain one to six kinds of metal powder selected from the group of copper, molybdenum, nickel, cobalt, iron and aluminum, each in an amount of one part. Due to this configuration, the reduction treatment agent can be easily mixed with various substances when added to those substances. Even if the target substance is not water, the agent can entirely and uniformly change that substance into a reduced state. Additionally, the reduction treatment agent can act as a surfactant, and therefore, can be used as cosmetics or food.
