Muhammad bin Sirin said: The most beneficial cupping is that which is done in the days when the month is waning.
Al-Tabarani recorded it in al-Mu'jam al-Saghir, under the entry of the person named Ibrahim. Its narrators are thiqat (trustworthy), except for al-Sari bin Yahya: he did not hear from Muhammad bin Sirin.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الطب / 8334