Question

what is the cause of internal bleeding in the stomach

Answer 1

it could be several things like being stabbed or shot or consuming rat poison or something really bad that you have to go to the hospital for.

Answer 2

not eating regularly, the HCL is released by the gastric Juice to kill the bacteria and germs anf if there is excess HCL in the stomach it will start internal bleeding which is the symptom of ulcer.
hope it helps:)