My mother is 75 years old. whenever she has a bowel movement her blood pressure drops suddenly and she feels faint. we have had to call 911 three times in the last month because of this. what is happening?

This needs to be investigated and cant be diagnosed without a thoro history physical and needed tests. Pl find a good doctor who will start all that asap

Syncope is likely and follow up in the office with her primary care doc will be needed as usually hospital work up will only rule out life threatening conditions. Detailed work up, review of her meds, possible addition of laxatives are required and they are best done by her main prescriber.