Juice fasting is a broad term to describe cleansing periods where you consume only fruit and vegetable juices, herbal teas, and water for a number of days to allow the digestive system to rest and recharge, while the detoxification organs filter out residual toxins. This article explains how to undergo a juice fast safely, as the body can react negatively to such drastic measures if certain precautions are not taken, such as extending the fast for too long or pushing yourself physically during the fast.