Beet Juice Side Effects. The benefits of beet juice are great, including it is a very powerful cleanser and blood builder. So much so, that you should be aware of some potential side-effects before you start drinking an abundance of beet root juice. The main side effect of beet juice is beeturia. This simply means it can change the color of your urine to pink or red. There is nothing harmful about beeturia. Avoid high levels of beet juice, especially if you have gall stones or kidney stones. High levels of beet juice can actually increase the incidence of these stones.