A lot of people experience severe fatigue after cleansing. I know, because I'm one of them. I've been doing liver and colon cleansing for 11 years, and when I release a lot of old toxins I usually feel fatigued for a while. Sometimes I feel very fatigued for a day or two. I've read that it takes a lot of energy to detoxify and release old toxins. That's certainly been my experience.