Probiotics that contain Bifodobacterium lactis appear to be the most effective for helping with constipation, according to Harvard Health Publications. Research found that probiotics helped soften stools, slowed “gut transit time” by 12.4 hours and increased the number of weekly bowel movements by 1.3.
Probiotics do not seem to be effective in preventing diarrhea in children, according to WebMD. However, to shorten the duration of childhood diarrhea, Saccharomyces boulardii, Lactobacillus GG, Lactobacillus reuteri, Lactobacillus casei or Lactobacillus rhamnosus may be helpful. To help keep kids safe from diarrhea caused by rotavirus, Bifidobacterium bifidum combined with Streptococcus thermophilus can be effective.