Beet Juice can be drank on an empty stomach but if you do drink some beet juice on an empty stomach it can sometimes cause stomach discomfort.
But other than that it's not harmful to drink beet juice on an empty stomach.
Although it's best to eat something and then drink the beet juice.
You'll reduce the stomach discomfort as well as help the beet juice work better and you'll get better and more health benefits when drinking beet juice after you eat something.
I like to have some cereal or toast first and then drink the glass of beet juice after I eat the cereal or toast or some other breakfast.