My Mother who is 62 has had red in her stool, she blames it on eating to many beets.
Can this be true and if so how long does it take to leave your system?

Okay, let's look at her stool. Not figuratively of course. Does it look like bright red blood?

Beets can very well cause red looking stool, this is VERY common if she does eat a lot of beets.

Is this a recent change?