Depending on your age, rectal bleeding can be nothing or can be concerning.
If you are 50+ or has colon cancer in your family, you should get a
colonoscopy to rule out cancer.
If you are in your 20s, 30s, rectal bleeding is likely due to anal fissure
or hemorrhoids. Dietary changes as your friend recommended will be the
right thing to do, especially if your stool is hard. It is not something
that you try for a couple of days. You have to keep doing that EVERY single
day ...
If you get bloody stool and diarrhea, you need to have it checked out,
because it can be serious issue.