Original Article: PDF OnlyIntestinal flora and endogenous vitamin synthesisHill, M J Author Information European Cancer Prevention Organization, Lady Sobell Gastrointestinal Unit, Wexham Park Hospital, Slough, Berkshire SL24HL, UK. European Journal of Cancer Prevention 6(2):p S43-S45, March 1997. Buy Abstract It is well established that the rumen microbial flora are a rich source of vitamins to the ruminant, and that the faecal bacterial flora are a major vitamin source for coprophagic rodents. There is also good evidence that the gut bacterial flora are a significant source of a range of vitamins to the human. In this paper evidence is presented that gut bacteria are a significant source of a range of vitamins, particularly those of the B group and vitamin K. © Lippincott-Raven Publishers.