1. Abdominal Pain/

2. Periumbilical Pain.ti,ab.

3. functional abdominal pain.mp.

4. Dyspepsia/

5. Irritable Bowel Syndrome/

6. exp Probiotics/

7. Lactobacillus/

8. Bifidobacterium/

9. Saccharomyces boulardii.ti,ab.

10. Streptococcus thermophilus/

11. or/6–10

12. randomized controlled trial.pt.

13. controlled clinical trial.pt.

14. randomized.ab.

15. placebo.ab.

16. drug therapy.fs.

17. randomly.ab.

18. trial.ab.

19. groups.ab.

21. or/12–19

22. exp animals/ not humans.sh.

23. 20 not 21

24. or/1–5

25. 11 and 22 and 23

26. limit 24 to English language

26. limit 25 to ‘all child (0–18 years)’