Beets are probably one of the most powerful vegetables available. Beets are known for causing both stools and urine to turn red and if this happens, don't be surprised.
Never drink beet juice by itself. Beet juice should always be mixed with other vegetables and/or apple juice. Pure beet juice (from the bulb or greens) can temporarily paralyze your vocal chords, make you break out in hives, increase your heart rate, cause chills or a fever.
Beets are best used in small amounts. I never use more than 1 to 2 ounces of beet juice (approximately ½ a small beet or ¼ a large beet).