Previous studies found that the proportion of genera Bifidobacterium and Lactobacillus vs. Escherichia is representative for the functional status of calve gastrointestinal tract and served as a way of its express appreciation. Therefore, this was the main argument in the realisation of this research, highlighting the dependency between the health of the digestive tract of children and the quantitative correlation between genera Bifidobacterium + Lactobacillus and Escherichia. The proposed goal was undertaken on children of various ages by determining the quantitative distribution in the intestinal content of named above microorganisms and the relationship between the quantity of Escherichia in relation to Bifidobacterium and Lactobacillus. Classical microbiological methods were used to calculate the number of microbial cells in 1g of intestinal content (in decimal logarithm - log). All parameters were determined with consideration for health indicators: healthy (sanogene), intermediary pathological (dismicrobism) and pathological (diarrheic dysfunction). The investigations results demonstrated that in children with sanogen health status, the number of Escherichia was within the limits 5.35 - 5.57; 5.63 - 5.89; 5.75 - 6.05; 6.01 - 6.25; 6.18 - 6.46; 6.46 - 6.78 log/g microbial cells (for 3–4, 5–6, 7–8, 9–10, 11–12 and 13–14 year old children respectively). The numerical value of bifidobacteria for the same groups of children, reached 8.52 - 8.78; 8.49 - 8.69; 8.03 - 8.31; 7.79 - 8.05; 7.75 - 7.99; 7.65 - 7.88 log/g and of lactobacilli - 7,62–7,90 7,76–8,00 7,53–7,75 6,67–6,97 6,37–6,69; 6.25 - 6.50 log/g. So these indices are varying according to the age of the subject. For those with intermediary pathological condition, the Escherichia amount was higher (7.84 - 8.06; 8.86 - 9.14; 9.01 - 9.33; 9.08 - 9, 42; 8.92 - 9.30; 9.08 - 9.38 log/g), and the quantity of bifidobacteria and lactobacilli diminished (6.35 - 6.71; 5.46 - 5.84; 6 69 - 6.99; 5.65 - 5.99; 6.45 - 6.89 ; 5.53 - 5.93; 6.36 - 6.62; 5.46 - 5.82; 6.48 -6.72; 5.31 - 5.61; 6.56 - 6.88; 5.24 - 5.52 log/g). The most extensive changes were observed in children in the final pathological state of health, when the number of bacteria of the genus Escherichia reached the maximum level (9.11 - 9.49; 9.32 - 9.74; 9.15 - 9 67, from 9.16 - 9.60, 9.09 - 9.51 and 9.30 - 9.76 log/g). Because the intestinal microbiocenoza represents a balanced system, in the case of the quantitative increase of Escherichia, simultaneously the number of bifidobacteria and lactobacilli was reduced. For patients with diarrheal dysfunction it was established the following values: 5.02 - 5.44; 3.13 - 3.63; 5.55 - 5.99; 3.38 - 3.86; 5.45 - 5.95; 3.33 - 3.75; 4.99 - 5.47; 3.20 - 3.66; 5.38 - 5.84; 3.57 - 4.07; 5.46 - 5.98; 3.76 - 4.16 log/g. The obtained data was used to calculate the quota of Escherichia in the intestinal contents of the children, according to age and health status of their digestive tract. For the subjects in healthy condition, this quota in relation to bifidobacteria was between 0.62 - 0.86; and to lactobacilli - 0.72 - 1.04 parts. This parameter increased in the case of dismicrobism (1.20–1.43 and 1.38 - 1.73 parts respectively), and the highest value was recorded for diarrheal dysfunction when the proportion of Escherichia to bifidobacteria and lactobacilli reached the level of 1.59 - 1.92 and 2.33 - 2.86 parts respectively. So, it was found that the ratio of quantitative indices of the genera Escherichia, Bifidobacterium and Lactobacillus in the intestinal contents vary according to the age of children and the health status of their digestive tract. On this basis it was recommended to use the numerical value of quota-part of Escherichia in relation to bifidobacteria and lactobacilli as an informative test for assessing the health status of the digestive tract.