Is it normal to poop on a pillow?
If it happened by accident, it’s not typical, but a one-off can happen when you’re sick or lose bowel control. If you mean doing it on purpose, that’s unusual; either way, clean the pillow thoroughly and pay attention to whether it happens again.
If you accidentally pooped on a pillow, that’s not a common bathroom mishap, but it can happen during stomach illness or a loss of bowel control. One episode doesn’t automatically mean something is wrong. If it keeps happening, or you suddenly can’t control your bowels, it’s worth checking in with a healthcare professional.
If you mean you chose to do it, that’s outside most people’s usual habits, but unusual doesn’t automatically mean there’s a problem. The practical issue is hygiene: wash or replace the pillow and bedding, and make sure anyone sharing the space is okay with what’s going on.