Why rectally and not orally?

The large intestine ‘colon’ has the most microbial colonisation in the digestive tract, 100 Billion cfu/ml. Probiotics taken orally need to survive the acidic environment of our stomach. The pH of the stomach is 1.0 -3.0. The pH of the colon is 5.5-7.5 (1,2,3). Probiotics taken rectally bypass the acidic environment in the stomach and the travelling distance of 7.5m approximately to the colon. Probiotics taken rectally ensure the destination is reached and the bacteria are still alive and stable.

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  3. J Gerritsen, H Smidt, G Rijkers, W de Vos. Intestinal microbiota in human health and disease: the impact of probiotics. Genes Nutr. 2011 Aug; 6(3): 209-240. Published online 2011 May 27. doi: 10.1007/s12263-011-0229-7