Q:
What is the ruling on the Sawm (Fast) of a person who makes an incision on a patient using a scalpel or similar instruments? Does this invalidate their Sawm?
A:
If a fasting person uses a scalpel or another similar instrument to make an incision across the vein of a patient (phlebotomy), this does not affect the validity of their Sawm. This is not a similar practice to cupping, where the cupper uses suction to draw blood from the person being cupped. It was mentioned in the book Kashf Al-Qina`: "Vertical or longitudinal incisions do not break Sawm." (Part No. 10; Page No. 263) May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.