The structure activity relationship of polyhydroxylated benzamide derivatives for whitening effects was examined. The adamantyl benzamide derivatives with catechol (3,4-dihydroxyphenyl) of B-ring part showed good anti-melanogenesis activity, but the inhibitory activity of mono-hydroxyphenyl (3-OH or 4-OH) or 3,4-dimethoxyphenyl substituted derivatives was decreased or lost. Therefore the catechol unit was appeared to be the crucial factor for the inhibition of melanogenesis. And the existence of 2-OH of A-ring part had minor influence on the activity, the length of carbon chain between A-ring and B-ring was also not the major factor for the anti-melanogenesis activity.