| Probiotics may reduce the incidence of antibiotic-related diarrhea. | A | 5–7, 9 | Most validated products are Saccharomyces boulardii and Lactobacillus rhamnosus GG |
| Probiotics may reduce the duration and severity of all-cause infectious diarrhea. | A | 5, 10–12 | A large meta-analysis of all-cause infectious diarrhea included studies with viral diarrhea and traveler's diarrhea |
| Probiotics may reduce the severity of pain and bloating in patients with irritable bowel syndrome. | B | 17–19 | Small trials to date |
| Probiotics may reduce the incidence of atopic dermatitis in at-risk infants. There is preliminary support for treatment of symptoms. | B | 20–23, 25–28 | — |