It is narrated from Hazrat Usama (may Allah be pleased with him) that the Holy Prophet (peace and blessings be upon him) said: The one who applies cupping and the one to whom it is applied, both their fasts are broken.
Hadith Referenceمسند احمد / مسند الأنصار رضي الله عنهم / 21826
Hadith Gradingحکم دارالسلام:صحيح لغيره، وهذا إسناد منقطع، الحسن لم يسمع من اسامة شياء، وقد اختلف فيه عليه