Figure 2. Secretory IgA content (A) and populations of Clostridium difficile (B), Bacteroides (C), Lactobacillus (D), and Bifidobacterium spp. (E) in the feces of healthy adults fed one daily probiotic capsule or placebo for 4 weeks as log CFU/g feces.

Values are means ± SEM, n=20 per group. Labeled means without a common letter differ, P<0.05. Time 1, first washout; Time 2, intervention; Time 3, second washout.