COMMENTARY. For the article “Flow, NO, and atherogenesis,” by John P. Cooke, which appeared in issue 3, February 4, 2003, of Proc. Natl. Acad. Sci. USA (100, 768–770; first published January 27, 2003; 10.1073/pnas.0430082100), the author should have noted that this work was supported by the National Heart, Lung, and Blood Institute (Grants R01 HL-63685, R01 HL-75774, R01 AT/HL00204, P01 AG18784, and P01 AI50153). Dr. Cooke is the inventor of patents owned by Stanford University for asymmetrical dimethylarginine (ADMA) assays and for the use of l-arginine in cardiovascular disease, for which he receives royalties. Dr. Cooke is a consultant for United Therapeutics.