Salam 1988.

Methods	Randomized controlled trial Generation of allocation sequence: random number table; block randomization with block size of 16 Allocation concealment: unclear in the published data but a personal communication from the author revealed that allocation concealment was done Blinding: participant, provider, and outcome assessor blinded Inclusion of all randomized participants: inadequate, 71% Duration: not reported
Participants	Number of participants enrolled: 90 Number of participants analysed: 64 Loss to follow up: 5 Inclusion criteria: age between 6 months and 12 years; history of blood, mucoid diarrhoea and a stool specimen that had grossly visible blood and mucus; illness duration less than 72 hours Exclusion criteria: severe malnutrition; with systemic illnesses in addition to shigellosis; who had received allopathic medications other than anti pyretics
Interventions	(1) Nalidixic acid (55 mg/kg/day, in 4 equally divided doses for 5 days) (2) Ampicillin (100 mg/kg/day in 4 equally divided doses for 5 days)
Outcomes	(1) Stool frequency (2) Clinical cure (3) Rectal prolapse (4) Fever (5) Bacteriological failure on day 3 (6) Bacteriological failure on day 6 (7) Adverse events
Notes	Location: Bangladesh Setting: participants were hospitalized for 6 days Follow‐up period: 6 days Antibiotic sensitivity pattern of Shigella isolates: all in both groups were sensitive to nalidixic acid. 25/40 in the ampicillin group were sensitive to ampicillin. Ampicillin sensitivity in the nalidixic acid group is not reported. Funding source(s): United Nations Children Fund (UNICEF); Dr Bennish is supported by grants from the Danish International Developmental Agency (DANIDA) and the U.S. Agency for International Development (UASAID) Chinoin Pharmaceutical and Chemical Works Ltd., Budapest, Hungary and Ambee Pharmaceuticals Ltd., Dhaka, Bangaldesh supplied the study drugs
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Low risk	"...random number table and block randomisation method with block size of 16".
Allocation concealment?	Low risk	"...patients were randomly assigned to receive either nalidixic acid or ampicillin" but the concealment method was not mentioned in the published data. Personal communication from the author revealed that allocation concealment was done. The drug was administered to the participating children by the research ward nurses, and the investigators only knew the random number pre‐assigned to one of the 2 drugs, by the randomization process.
Blinding? All outcomes	Low risk	"...drugs were administered as syrups that had similar colour, consistency, and flavour, and the concentration of each drug was adjusted so that patients received the same volume... patients, staff and investigators were unaware of which drug was being given."
Incomplete outcome data addressed? All outcomes	High risk	"data were analysed only from patients with culture‐confirmed cases of shigellosis who remained in the study for at least 24 hours." 90 enrolled, 74 eligible for analysis, 64 analysed. 10 drop‐outs ‐ 6 withdrawn by their parents, reasons not provided, 4 withdrawn because of lack of clinical improvement. 82% follow up.
Free of selective reporting?	Low risk	The study's prespecified outcomes, which were of interest in this review, have been reported
Free of other bias?	Low risk	The study appears to be free of other sources of bias