Colon cancer is a major cause of morbidity and mortality. Compounds present in plant foods have anti-carcinogenic properties that may be metabolised by colonic bacteria thus decreasing or preventing any such beneficial effects. Phytic acid is found mostly in legumes and appears to possess anti-carcinogenic properties. This may be due to a number of factors including the recognised ‘binding’ properties of phytate. For this to occur successfully it is important that the integrity of phytic acid is preserved in the colon, which is a profuse microbial ecosystem. However, there are few data on the microbial species involved in its metabolism. Studies that define the populations involved may lead towards the use of dietary intervention procedures that can reduce the activities of the microflora involved in phytate degradation, thereby preserving its purported anti-tumour properties.