The Prophet ﷺ said: If anyone has himself cupped on the 17th, 19th and 21st it will be a remedy for every disease. (Using translation from Abū Dāʾūd 3861)
قَالَ رَسُولُ اللهِ ﷺ مَنِ احْتَجَمَ لِسَبْعَ عَشْرَةَ وَتِسْعَ عَشْرَةَ وَإِحْدَى وَعِشْرِينَ كَانَ شِفَاءً مِنْ كُلِّ دَاءٍ