Biliary decompression and drainage done in a timely manner is the cornerstone of acute cholangitis treatment. The mortality rate of acute cholangitis was extremely high when no interventional procedures, other than open drainage, were available. At present, endoscopic drainage is the procedure of first choice, in view of its safety and effectiveness. In patients with severe (grade III) disease, defined according to the severity assessment criteria in the Guidelines, biliary drainage should be done promptly with respiration management, while patients with moderate (grade II) disease also need to undergo drainage promptly with close monitoring of their responses to the primary care. For endoscopic drainage, endoscopic nasobiliary drainage (ENBD) or stent placement procedures are performed. Randomized controlled trials (RCTs) have reported no difference in the drainage effect of these two procedures, but case-series studies have indicated the frequent occurrence of hemorrhage associated with endoscopic sphincterotomy (EST), and complications such as pancreatitis. Although the usefulness of percutaneous transhepatic drainage is supported by the case-series studies, its lower success rate and higher complication rates makes it a second-option procedure.