['Several experimental studies have shown the importance of arginine in wound healing. However, little is known about its role in human wound healing. In this study, we investigated arginine metabolism in impaired wound healing.', 'Twenty patients with chronic wounds and 10 patients with acute wounds were included in a prospective study. Amino acids, nitrate/nitrite, and arginase concentrations were determined in plasma and wound fluid using high-performance liquid chromatography and enzyme-linked immunosorbent assay. Chronic wounds were divided into two groups: noninfected chronic wounds (n = 11) and infected chronic wounds (n = 9), based on quantitative bacterial analysis of wound fluid samples.', 'Plasma arginine levels, next to total plasma amino acid levels, were significantly decreased in patients with infected chronic wounds compared with patients having acute or noninfected wounds. Citrulline and ornithine levels were significantly increased in infected chronic wounds and related to decreased nitrate/nitrite levels, whereas wound fluid arginine levels were similar in all groups. In addition, wound fluid arginase levels of infected chronic wounds were significantly enhanced.'] Do infected chronic wounds show different local and systemic arginine conversion compared with acute wounds?