GYY4137 sodium (Na-GYY4137) is a dichloromethane-free, water-soluble sodium salt form of the slow-releasing hydrogen sulfide (H2S) donor GYY4137. Na-GYY4137 is devoid of potential off-target effects associated with the use of dichloromethane-complexed GYY4137 morpholine salt form. Morpholine is biologically active and toxic (LD50 range of 300-500 mg/kg in rodents), while dichloromethane is carcinogenic and can metabolize in vivo to carbon monoxide, causing unintended CO-dependent effects.