Apart from the activity of phenolic compounds, another coffee bioactive compound such as caffeine could contribute to themutagen inhibition. Caffeine standard solutions had high inhibition percentages (33–56%) against the mutagenic agent, showing a dose-dependent pattern. In order to better simulate different spent coffee and coffee brew matrices, mixtures of low, medium and high concentrations of 5-caffeoylquinic acid and caffeine were also tested.The results from 5-CQA and caffeine mixtures did not show any additional or synergistic effects, because similar inhibition percentages have been found when comparing with individual standards (40–53%).