Table 1

Timetable of activities planned during the study

	Study period
	Enrolment	Allocation	Postallocation Antibiotic therapy					Close-out (after the end of follow-up period)
Time point	Day 1	Day 1	Day 2	Day 3	Day 4	Day 5	Every day	Close-out (after the end of follow-up period)
Enrolment
Eligibility screen	X
Informed consent	X
Randomisation of the participant	X
Study product distribution	X
Diary of symptoms	X
Interventions
Lactobacillus reuteri DSM 17938
Placebo
Assessments
Adverse events			X	X	X	X	X	X
Stool analysis in case of diarrhoea/AAD			X	X	X	X	X	X
Daily diary reporting			X	X	X	X	X	X
Telephone contact to check diary reporting and compliance in outpatients			X	X	X	X	X	X
Return of non-used study products								X

AAD, antibiotic-associated diarrhoea.