Human intestinal methanogens and lactulose administration.

The effect of lactulose on human intestinal methanogenic bacteria in ten subjects on lactulose therapy and ten control adults was evaluated. Methanogens were found in 90% of the population examined (9 treated subjects and 9 controls). A marked variability in methanogen number (ranging from 10(3)-10(10)/gdw) was observed in lactulose-treated subjects and in controls. Analysis of variance showed no significant difference between the two groups.