Human UDP-glucuronosyltransferases (UGTs) are important phase Ⅱ drug-metabolizing enzyme involved in the glucuronidation of drugs, toxicants, and some important endogenous substances (e.g., bilirubin, estrogen, bile acids, et al.).Altered activity of UGT isoforms will result in the disrupted elimination of endogenous and exogenous compounds.For example,indinavir, an HIV therapeutic drug, can significantly induce the elevation of unconjugated bilirubin in serum through inhibition of UGT1A1-mediated bilirubin glucuronidation.Inhibition of UGT1A1 by sorafenib has been speculated to be main reason sorafenib-induced elevation of serum bilirubin.In this presentation, we will report the inhibitors of UGTs from exogenous and endogenous substances, including drugs, herbal components, bile acids, and lipid components.Additionally, the idea on UGTs inhibition-guided structural modification was given in this presentation using andrographolide derivatives as examples.In conclusion, this presentation highlighted the importance of UGTs in the diseases and xenobiotics-induced adverse effects.