Epidemiological studies suggest an inverse association between coffee consumption and risk of colorectal cancer. This led to the hypothesis that coffee components could have chemoprotective properties. The coffee diterpenes present in oil derived from coffee have been investigated extensively in vitro and in animal models. Several mechanisms by which these compounds could protect against carcinogenesis have been proposed, such as induction of detoxification pathways, increased apoptosis, reduced angiogenesis and protection against oxidative stress. However, none of these pathways have been convincingly demonstrated to protect against carcinogenesis in humans and the chemoprotective properties of coffee diterpenes currently remain hypothetical.