Does a gastroscopy invalidate the fast?

A gastroscope is a medical device inserted into the stomach through the mouth for imaging or taking a sample, and it is removed after its function is completed. Scholars have differed on whether it breaks the fast. The three schools of thought (Maliki, Shafi'i, and Hanbali) hold that it invalidates the fast if anything reaches the stomach. Whereas the Hanafis stipulate that something must settle in the stomach to break the fast, and therefore the endoscope is not considered to invalidate it. Sheikh al-Islam Ibn Taymiyyah chose the view that only that which is nourishing breaks the fast, and this is the most preponderant opinion because the endoscope is not eating or drinking.

If the endoscope is accompanied by the introduction of fatty substances or solutions, these invalidate the fast because the body absorbs them and is nourished by them. The resolution of the Islamic Fiqh Council (Majma' al-Fiqh al-Islami) stipulated that a gastroscopy does not break the fast unless it is accompanied by the introduction of liquids or other substances. In conclusion, the gastroscopy itself does not break the fast, but the introduction of any substances with it invalidates the fast.