Abstract: A phototherapeutic toothbrush comprises a handle, a circuit board and a brush jacket. The handle can accommodate the circuit board, which is fitted with an extension board extending outside of the handle. The extension board is equipped with at least one light source. When brush jacket with a brush head is linked to the handle, the light source can duly generate phototherapeutic and bactericidal light to irradiate and cure the mouth surfaces and sterilize the bristle of brush head.