Cognomen ฤทธิ์รักษ์ (ฤทธิ์รักษ์ 
) , in all the world, is a very rare last name. The surname ฤทธิ์รักษ์ is characteristic of South-eastern Asia, particularly Thailand, where it is a rare surname. Very seldom, ฤทธิ์รักษ์ is the forename as well as the last name.