The study of glucuronidation over the next 10 years will need to consider the biochemical physiology of whole cell (eg hepatocytes) and whole organs including extrahepatic tissues to reveal important rate limiting mechanisms. Specificity of uptake and transport of substrates to endoplasmic reticulum; specificity of UDP-glucuronosyltransferases and specificity of selective sorting and excretion of glucuronides all need to be thoroughly examined to elucidate the process of drug elimination by glucuronidation.