Our defense against the toxic effects of small organic molecules is mediated by families of enzymes found in the internal membranes of cells. Many small organic molecules, such as environmental pollutants, carcinogens and therapeutic drugs, are fat-soluble and will accumulate in the body to toxic levels unless they are modified, usually by the addition of sugar groups. The modified chemical, in the majority of cases, is less toxic and readily removed from the body. We have identified and characterized many of the sugar-transferring enzymes involved in this detoxification process. We are investigating how these enzymes are controlled in the cell and whether there are genetic differences in control processes that may impact on our ability to detoxify drugs and chemicals. This research may provide strategies to help reduce the risk of chemical-induced carcinogenesis and hormone-dependent cancers, such as those of the prostate and breast.