If you go to the doctor because you have been vomitting everyday for a week

Question

why would they need to stick a finger in your butt to check for blood?

Answer 1

thats not how they check for blood in your r****m or stool.

Answer 2

you should ask your doctor before you let them stick their finger up your butt

Answer 3

WTF!!!!!

Answer 4

They're getting some stool to make sure you don't have an inflammatory process going on in your gut.  Something like Crohns disease would cause nausea, vomiting, abdominal pain.  Inflammation in your gut would cause small amounts of blood to be present in your stool without you actually seeing anything.

Most docs are not terribly thrilled about the rectal exam.  But it has to be done to rule out masses and check for occult blood in a timely manner.  

The alternative is for you to scoop pieces of your p**p onto a card, store the p**p card in a plastic bag and bring it back to the laboratory.