Asymmetric dimethylarginine (ADMA), which is a product of post-translational methylation of arginine residues, inhibits nitric oxide synthases. This Review highlights the potential of modulating ADMA activity — by targeting the enzyme that metabolizes ADMA, dimethylarginine dimethylaminohydrolase — as a novel mechanism to regulate nitric oxide bioavailability in various pathologies, including sepsis.