Table 2 Example of the search strategy for MEDLINE through Ovid

1. exp Diarrhea/

2. diarrh$.mp.

3. exp Gastroenteritis/

4. gastroenteritis.mp.

5. gastrointestinal infection$.mp.

6. enteritis.mp.

7. dysenter$.mp.

8. or/1-7

9. pr$biotic$.mp. or exp Probiotics/

10. exp Lactobacillus/

11. lactobacteri$.mp.

12. lactobacill$.mp.

13. reuteri.mp.

14. exp Saccharomyces/

15. exp Bifidobacterium/

16. saccharomyc$.mp.

17. boulardii.mp.

18. exp Bacillus/ or Bacillus.mp.

19. Subtilis.mp.

20. clausii.mp.

21. exp Enterococcus faecium/

22. enterococcus faecium.mp.

23. bifidobact$.mp.

24. rhamnosus.mp.

25. casei.mp.

26. thermophilus.mp.

27. acidophilus.mp.

28. plantarum.mp.

29. bulgaricus.mp.

30. lgg.mp.

31. bifidum.mp.

32. sy?biotic$.mp.

33. or/9-32

34. exp Silicates/

35. silicate$.mp.

36. diosmectite.mp.

37. smectite.mp.

38. smecta.mp.

39. or/34-38

40. racecadotril.mp.

41. acetorphan.mp.

42. enkephalinase inhibitor$.mp.

43. exp Thiorphan/

44. thiorphan.mp.

45. tiorfan.mp.

46. tiorfix.mp.

47. hidrasec.mp.

48. or/40-47

49. exp Loperamide/

50. loperamide.mp.

51. imodium.mp.

52. or/49-51

53. exp Antidiarrheals/

54. antidiarrh$.tw.

55. or/53-54

56. exp Zinc/

57. exp Zinc Compounds/

58. exp Zinc Acetate/

59. zinc.mp.

60. gluconate.mp.

61. cinc.mp.

62. Trace Elements/

63. or/56-62

64. exp Vitamin A/

65. retinol.mp.

66. vitamin A.mp.

67. or/64-66

68. exp Yogurt/

69. exp Cultured Milk Products/

70. yogurt$.tw.

71. yogh?urt$.tw.

72. k?umis$.tw.

73. Kumys$.mp.

74. k?efir$.tw.

75. kephir.tw.

76. bulgaricus.tw.

77. doog.tw.

78. lassi.tw.

79. Matso?n$.tw.

80. Da?hi.tw.

81. viili.tw.

82. (Fermented adj2 milk).tw.

83. delbruecki$.tw.

84. (sour adj1 milk).tw.

85. or/68-84

86. exp Milk Substitutes/

87. exp Lactose Intolerance/

88. (Soy adj3 milk).tw.

89. (Soy adj3 formula).tw.

90. (lactose adj1 intolerance).mp.

91. (lactose$ adj2 formula).tw.

92. or/86-91

93. 33 or 39 or 48 or 52 or 55 or 63 or 67 or 85 or 92

94. 8 and 93

95. randomized controlled trial.pt.

96. randomized.mp.

97. blind$.mp.

98. placebo.mp.

99. or/95-98

100. 94 and 99

101. (Infan$ or newborn$ or new-born$ or perinat$ or neonat$ or baby or baby$ or babies or toddler$ or minors or minors$ or boy or boys or boyfriend or boyhood or girl$ or kid or kids or child or child$ or children$ or schoolchild$ or schoolchild).mp. or schoolchild.tw. or schoolchild$.tw. or adolescen$.mp. or juvenil$.mp. or youth$.mp. or teen$.mp. or under$age$.mp. or pubescen$.mp. or exp Pediatrics/ or pediatric$.mp. or paediatric$.mp. or peadiatric$.mp. or school.tw. or school$.tw. or prematur$.mp. or preterm$.mp.

102. 100 and 101

103. limit 102 to human