[freecw (OP)]

In your digestive tract most of the bacteria are located in your large intestine because most of them can't survive the acidic conditions of stomach and not sure whether or not there are some in the small intestine but none that I'm aware of. Since all of the absorption of nutrients from foods occure in the small intestine (most in the begining parts), how does the bacterial flora located in the large intestine help with digestion? Only water is absorbed in the Large intestine so even if they do break down what our enzymes can't break down, how are those fats and other fermentation products absorbed and used by our bodies? If they aren't absorbed by the body then how can they be so important to our bodies?

[Mr. Data]

Certainly, a wide range of products can penetrate the bodies skin. Surely you don't expect one chemical reaction to be involved in this?

[imatfaal]

Free - we do absorb most useful stuff before the large intestine, but the large intestine doesn't just absorb water and create feces.  It is where fiber and long chain polysaccharides are digested by bacteria to give short chain fatty acids which are absorbed into the blood stream.  Various vitamins are also manufactured there by bacteria and absorbed into the blood stream

[Bored chemist]

Certainly, a wide range of products can penetrate the bodies skin. Surely you don't expect one chemical reaction to be involved in this?

The skin hasn't a lot to do with the topic and nobody said anything about "one chemical reaction".