If the diarrhea is mild, and will not affect the fast or cause exhaustion or undue hardship, it is not permissible for you to break your fast. But if the diarrhea is severe, to the extent that you feel tired and exhausted, you have to break your fast.

1- If you suffer from kidney disease or diabetes and similar diseases where fasting will cause harm, you are allowed to break the fast. 2- The correct view regarding taking blood from veins for testing is that this does not break the fast, but if it is done often, it is better to leave it until night-time.

There is nothing wrong with using nasal sprays that contain that percentage of alcohol. Using nasal sprays for allergies does not invalidate the fast whether they are administered through the nose or through the mouth.