UDP-glucuronosyltransferases (UGTs) are important phase II metabolic enzymes responsible for approximately 40-70% of endo and xenobiotic reactions. It catalyzes the transfer of glucuronic acid to lipophilic substrates, converting them into hydrophilic compounds that are excreted. There are 22 active human UGTs that belong to 4 families. This review focuses on human UGTs, highlighting the most current issues in order to connect all information available and allowing a discussion on the challenges already solved and those in which we need to move forward. Although, several UGTs studies have been conducted, the most recent ones addressing drug-drug interactions and polymorphism issues, there are still bottlenecks to overcome. Tridimensional structure is difficult to obtain due to overexpression, purification, and crystallization problems as well as the action mechanism - since overlapping of substrate specificities renders impasses on the identification of which isoform is responsible for a particular drug metabolic pathway. For this reason, bioinformatic tools are gaining more space, since it is a faster and less expensive reliable methodology that complements in vitro and in vivo researches. Combinations of quantum and molecular methods have become increasingly common, leading to the incorporation of enzyme features comprising their structure, dynamics and chemical reactions. Breakthroughs related to the enzyme, not only enable the discovery of new drugs essential for the treatment of various diseases, but also provide an improved action of the existing drugs.