Ibn Umar r.a reported that the Messenger s.a.w said, “Hijamah (cupping) on an empty stomach* is best. It increases the intellect and improves the memory. It improves the memory of the one memorising. So whoever is going to be cupped then (let it be) on a Thursday in the name of Allah. Keep away from being cupped on a Friday, Saturday and Sunday. Be cupped on a Monday or Tuesday. Do not be cupped on a Wednesday because it is the day that Ayoub was befallen with a trial. You will not find leprosy except (by being cupped) on Wednesday or Wednesday night.” [Saheeh Sunan ibn Maajah (3488)].
* ‘alaa ar-reeq in arabic means to fast until after being treated with cupping. Once the treatment of cupping has been completed, one may eat and drink.
It is forbidden for a person to be cupped to take in any morsel whatsoever in the morning of cupping, but to remain fasting until it is performed upon him. He is permitted to drink a cup of coffee or tea for the sugar it contains is little and it does not need complicated digestive operations which stir the blood, activate the blood circulation, affect the blood pressure, and the heart beats. Also this little quantity of tea or coffee contains a simple nerve stimulant which makes the person undergo cupping in a wakeful case.
For this reason the Prophet Muhammad s.a.w prohibited eating before applying cupping for it activates the digestive system and the blood circulation in order to recompense the digestive operations which lead to the increase in heart beats, blood flow, and a high blood pressure. This case will move the precipitated residues of the sluggish and retired blood in the superficial and deep blood vessels and capillaries in the region of the upper back (these unwanted materials of blood gather during sleeping). Also blood flow is activated during the distribution of the digested nutrients in order to feed the body tissues. Such a situation does not fit cupping. If cupping is performed in similar condition, the blood isn’t filtered by this operation (Cupping), so the withdrawn blood is the working blood (not the spoiled blood which is full of impurities as dead red blood cells and R.B. cell ghosts) and we have lost the expected benefit from cupping. In this case, the cupped person will also suffer from slight vertigo or syncope as a result of the insufficient quantity of blood which irrigates the brain.