This makes the toxin or drug water-soluble, so it can then be excreted from the body via watery fluids such as bile or urine. Inside the liver cells there are sophisticated mechanisms that have evolved over millions of years to break down toxic substances. Every drug, artificial chemical, pesticide and hormone, is broken down by enzyme pathways inside the liver cells. Fat soluble chemicals have a high affinity for fat tissues and cell membranes, which are made of fatty substances. In these fatty parts of the body, toxins may be stored for years, being released during times of exercise, stress or fasting. However, there are no clinical data to support the efficacy of these cleanses. In fact, some dietary supplements can actually cause harm to the liver by leading to drug-induced injury and should thus be used with caution.