Probably the most important reason to wait at least 3 weeks between flushes is to build up mineral reserves. you see by flushing the liver you release alot of toxins and alot of minrals reserves your body has spent a while building up (especially if you are on a bad diet) these minerals are needed to ''buffer'' the acidic waste that the L.F produces. If there are not enough mineral reserves, due to flushing to frequesntly or not having a healthy mineral rish diet to buffer the released toxins they can re - enter the blood stream... therefore possibly causing even worse state than before flushing. that is why the most important thing is to eat healthily before any cleanses...