Compounds from spent coffee grounds are fermented by colon human microbiota. Human gut fermented- non-digestible spent coffee grounds inhibited SW480 survival. A decrease in reduced-glutathione/oxidized-glutathione (GSH/GSSG) ratio was shown. Flow cytometry indicates the presence of dead cells with a DNA content lower than 2n. Human gut fermented- non-digestible spent coffee grounds induced apoptosis.