Anas ibn Maalik r.a reported that the Messenger s.a.w said, “Whoever  wants to perform hijamah (cupping) then let him search for the 17th, 19th and 21st day (of the Islamic, lunar month) and let none of you allow his blood to rage (boil) such that it kills him.” [Saheeh Sunan ibn Maajah (3486)].

Abu Hurairah r.a reported that the Messenger s.a.w said, “Whoever performs hijamah (cupping) on the 17th, 19th or 21st day (of the Islamic, lunar month) then it is a cure for every disease.” [Saheeh Sunan abi Dawud (3861)].