is it counted among the things a fasting person is allowed to do, or is it one of the nullifiers of the fast? Please clarify this for us; may Allah reward you.

Answer: As for drawing blood from someone who is fasting, if a large amount is taken, it breaks the fast. Thus, if blood is withdrawn from a fasting person in order to donate to a blood bank, or to give urgent transfusion to a patient in need, and a significant quantity is removed, that affects him and invalidates his fast just like cupping (ḥijāmah). Cupping is clearly established by textual evidence, and the sound report from the Prophet ﷺ—narrated by many Companions—states that cupping breaks the fast; the same ruling applies to blood withdrawal when the amount is substantial, for it corrupts the fast.

With regard to injections administered to the fasting person—namely, needles—then if they are nutritional injections, there is no doubt they break the fast because they take the place of food and drink in revitalising and nourishing the body; therefore they carry the same ruling as eating and drinking. Likewise, injections that are not nutritional but are given as medication and are introduced through the bloodstream, through a vein, also break the fast. They travel with the blood, reach the internal cavity, and have an effect on the body similar to that of food and drink. Just as swallowing tablets by mouth nullifies the fast, so too taking medicine by injection has the same effect.

As for injections given intramuscularly rather than intravenously, and which are not nutritional, some scholars have granted a concession concerning them. However, the view I hold is that they fall under the same ruling as the other injections, because they affect the body and produce a physiological result; it is as though the medicine entered via the bloodstream. There is no difference between taking medication through a vein and taking it through a muscle.