The results of 1H spin-echo Fourier transform (SEFT) nuclear magnetic resonance (nmr) experiments suggest that some aurothiomalate binds intracellular glutathione (GSH) when added to suspensions of red cells in vitro. When added to red cell lysates, a specific binding of gold to cysteine of GSH is observed together with release of thiomalate. Gold binding to GSH can be reversed by addition of dimercaptopropanol sulfonate. Spectra are compared to those of an aurothiomalate-GSH model system. The relationship of these findings to the mechanism of action of Myocrisin is discussed.