The present invention relates to a tooth whitener in W/O emulsion phase or lamellar liquid crystal phase which comprises a glycerol monooleate, a polyol, a polymer, a peroxide, an optional peroxide stabilizer, and a hydrophilic solvent, wherein the glycerol monooleate is in an amount of 15 to 95% by weight based on total weight of the tooth whitener, the polyol is in an amount of 0.05 to 20% by weight based on total weight of the tooth whitener, the polymer is in an amount of 0.2 to 40% by weight based on total weight of the tooth whitener, the peroxide is in an amount of 1 to 30% by weight based on total weight of the tooth whitener, the peroxide stabilizer is in an amount of 0.1 to 10% by weight based on the weight of peroxide, the hydrophilic solvent is in an amount of 1 to 50% by weight based on total weight of the tooth whitener.
