Experimental diets containing 1 or 2 -0x1.8c6d0000008p+0cetic acid were fed to Single comb White Leghorn hens ad libitum and collected the contents in jejunum and ileum. Contents were diluted and dilution were cultured for 48 hours at 38 C in anaerobic condition. The colonies of anaerobic bacteria in jejunum were decreased with addition of acetic acid whereas that in ileum was not changed. These results suggested the possibility that added acetic acid was absorbed at upper part of intestine so acetic acid showed no effect at ileum, lower part of intestine.