This study was undertaken to assess the effect of the Korean red ginseng extracts on the growth of lactic acid bacteria, such as Lac. acidophilus and Str. thermophilus. The results are summarized as follows: 1. The growth of all the lactic acid bacteria tested in this study was not influenced when the skim milk was added with the red ginseng extracts in concentration of less than 4.0%. But the growth was remarkably inhibited in the presence of 8.0% red ginseng extracts in skim milk. 2. Titratable acidity was more or less increased by addition of red ginseng extracts as compared with control except when the amount of 8.0% red ginseng extracts were added into skim milk. 3. No particular effect was observed in the growth of lactic acid bacteria in case of addition of saponins. But the remarkable inhibitory effect was observed in the skim milk with the amount of 1.2mg/ml the fractions extracted by ethyl ether from red ginseng extracts.