N(ω)-hydroxy-nor-L-arginine (nor-NOHA), an arginase inhibitor, has therapeutic potential in the treatment of cardiovascular and obstructive airway diseases. Nor-NOHA is a reversible, competitive arginase inhibitor. The affinity of nor-NOHA for the to the arginase active site was found in the nanomolar range. Nor-NOHA has proven to be one of the strongest arginase inhibitors. Inhibition by nor-NOHA is ten times more potent on arginase II than on arginase I. The pharmacokinetics of nor-NOHA is characterized by high bioavailability, close to 100% after multiple dose and rapid elimination resulting in t1/2 of 15–30 min after intravenous and intraperitoneal administration to rats. Arginase inhibition with Nor-NOHA increased circulating arginine levels and decreased hepatic damage during liver I/R injury. Arginase blockade represents a potentially novel strategy to combat hepatic I/R injury associated with liver transplantation. Nor-NOHA is under investigation in clinical trial NCT02009527 (Arginase inhibition in ischemia-reperfusion injury).