Acute Necrotizing Pancreatitis Is A Very Serious Disease That May Lead To Severe Systemic And Catastrophic Local Complications. One Of The Rare Local Complications Is Left Gastric Pseudoaneurysm, Another Even More Rare Complication Is Colonic Perforation. Here, We Present A Case Of Acute On Alcoholic Chronic Pancreatitis Complicated By Large Pseudocyst, Presented With Severe Lower Gastrointestinal Bleeding And Hemorrhagic Shock, Treated By Urgent Exploration Which Revealed The Presence Of Both Left Gastric Pseudoaneurysm And Colonic Perforation And Dealt With By Transfixing Ligation Of Bleeding Vessel And Loop Ileostomy.