Heidarifar 2014.

Methods	RCT
Participants	Included: single and being educated in the Nursing and Midwifery School and Paramedical Faculty of Qom University of Medical Sciences in 2011 (Qom city is almost situated in the centre of Iran with about 150 km distance from Tehran). Excluded: participants with a history of pelvic or organic disorders; any known gastrointestinal, urogenital, hematological, or other systems disorders; irregular menstrual cycles; taking any drug; and previous sensitivity to NSAIDs or dill; or mildly dysmenorrhoeal. Age: the mean age of the dill group = 20.95 years, mefenamic acid group = 22.04 years, placebo group = 20.95 years Source: Nursing and Midwifery School and Paramedical Faculty of Qom University of Medical Sciences of Iran Location: Iran
Interventions	Group 1: dill capsules that contained 500 mg dill seed powder (treated 2 capsules orally q12h (totally 1000 mg q12h)) (N = 25, 23 analysed) Group 2: 250 mg mefenamic acid capsule (orally q12h) (N = 25, 24 analysed) Group 3: starch as placebo (500 mg q12h) (N = 25, 23 analysed) The participants were treated since 2 days before the beginning of their menstruation for 5 days. Participants were followed for two cycles (2 months) and asked to answer the questionnaires at the end of every cycle.
Outcomes	Severity of dysmenorrhoea (pain) measured by VAS (scale 10 cm) and verbal multi‐dimensional scoring (VMS), 0 to 3 where 0 = no pain and 3 = severe pain).
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	“This double‐blind, randomised study was conducted among 75 female students between 18 and 28 years old.” Comment: the study authors did not describe the method of sequence generation.
Allocation concealment (selection bias)	Unclear risk	“The participants were allocated randomly into one of the following groups”. “In regarding the blinding process, the researchers and the participants were uninformed of allocating manner of each group and a third one that did not involve in analysing and interpreting, etc., allocated the participants in groups and allotted a code number to everyone.” Comment: there was insufficient detail regarding whether allocation sequence was concealed or not.
Blinding (performance bias and detection bias) All outcomes	Low risk	“All of the capsules were made by Boo Ali Research Center of Qom city and were completely similar in shape. In regarding the blinding process, the researchers and the participants were uninformed of allocating manner of each group and a third one that did not involve in analysing and interpreting”.
Incomplete outcome data (attrition bias) All outcomes	Low risk	“Of 75 participants of this study, five of them did not continue the study due to fearing of its side‐effects; therefore we evaluated 70 students”. Comment: the dropout rate was 6.67% (5/75).
Selective reporting (reporting bias)	Unclear risk	“In assessing the side‐effects, in Dill group, two students reported menstrual changes as increasing in amount and duration of bleeding and one student reported gastrointestinal discomfort. In mefenamic acid group, menstrual changes and gastrointestinal discomfort were reported in one and two students, respectively. In placebo group, each of the mentioned side‐effects was only observed in one student.” Comment: the study authors did not prespecify adverse events and rate of satisfaction as the outcomes, but reported them in the text and table 3, respectively. In addition, the number of participants in each group was not entirely clear.
Other bias	Low risk	Comment: we did not identify any other potential sources of bias.