Comparison 1. Probiotics versus placebo for prevention of diarrhoea induced by radiotherapy (with or without chemotherapy).

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Any diarrhoea	3		Risk Ratio (M‐H, Random, 95% CI)	Totals not selected
2 Diarrhoea grade 2 or higher	4	420	Risk Ratio (M‐H, Random, 95% CI)	0.75 [0.55, 1.03]
3 Diarrhoea grade 3 or higher	3		Risk Ratio (M‐H, Random, 95% CI)	Totals not selected
4 Requiring rescue medication for diarrhoea	3	194	Risk Ratio (M‐H, Random, 95% CI)	0.50 [0.15, 1.66]
4.1 New subgroup	3	194	Risk Ratio (M‐H, Random, 95% CI)	0.50 [0.15, 1.66]