Objectives and method: To determine the effect of total extract of milk thistle fruits on the velocity of glycine absorption in the chronic experiments under physiological condition with no operation trauma, pain, narcosis and atrophy of the small intestine. Results:In the presence of total extract of milk thistle fruits the glycine absorption velocity increases during one hour of perfusion. Absolute values of glycine absorption are higher in the presence of milk thistle fruits extract then in its absence. We observed no dissolution of perfusate with gastrointestinal fluids in the small intestine functioning part indicating that absorption of water in this fragment of small intestine prevails in the presence and in the absence of milk thistle extract both. Conclusions:Total extract of milk thistle fruits activates the velocity of absorption of glycine in the functioning fragment of the rats′ small intestine under physiological conditions.