The fermented tomato juice has been known to contain lactic acid bacteria as much as 2,2 x 109cfu/ml. In this observation, the fermented tomato juice tested by in vivo using mice to look at its effects. It is firstly divided into two steps; the first step is to give the aquades, commercial fermentation product, and fermented tomato juice to mice for 28 days and the second step is to see the influence of fermented tomato juice to mice (the condition of physical and activity, weight body and the feed consumption, intestinal microflora, and the condition of small intestine). The obtained result showed that the condition of physical and activity is good and not subjected to depression. The weight body of mice given fermented tomato juice tends to more decrease than aquades and commercial fermentation product. The feed consumption of mice with fermented tomato juice mainly decreases while the mice are given akuades and fermentation products of commercial consumption mainly increasing and stable. The total of microbes, lactic acid bacteria, yeast and mold in intestines of mice is 107 cfu/ml. The total of E. coli and Staphylococcus in intestines of mice is 106 cfu/ml. The condition of villi in mice given tomato juice fermentation (614,41 mikron) is longer than aquades (583,58 mikron) and commercial fermentation products (604,69 mikron).