Before determining the IC50‘s for the Aldehyde Dehydrogenase (ALDH) inhibitor, we performed some initial experiments to establish appropriate assay conditions. We assessed conditions for baker’s yeast potassium activated ALDH. First, we titrated the enzyme using 20 mM acetaldehyde as the substrate. From these titrations, we decided to use 1.3 U/reaction of ALDH. We next titrated the solvent DMSO to determine any inhibitory effects it may have on ALDH. The Km of acetaldehyde for ALDH was then measured in the presence of the highest tolerable DMSO concentration. Finally, the IC50 for a known ALDH inhibitor, disulfiram, was measured. We determined the maximum DMSO concentration for the test compounds to be 100 v% (final reaction concentration of 5 v%). We determined the acetaldehyde Km to be 900 ± 92 µM. Using 900 µM acetaldehyde, we observed an IC50 = 2.65 µM for disulfiram.