Table 1: Study characteristics.

StudyParticipant characteristicsSample sizeGinger preparation and doseComparisonOutcome measureAuthor conclusionsSide effects
Ginger group Control group

Jenabi, 2013 [22](i) College students in Iran
(ii) Having moderate to severe dysmenorrhea
3534Capsule of ginger powder (unknown origin and constituents)
500 mg TID × 3 days (first 3 days of a period)
PlaceboPain severity (VAS)(i) The mean change in pain severity in ginger group was significantly greater than the placebo group. None reported

Rahnama et al., 2012 [15](i) College students (>18 yo) in Iran living in the dorms
(ii) With primary dysmenorrhea
(iii) Having moderate to severe dysmenorrhea
(iv) BMI between 19 and 25
(v) Not on OCPs
5946Capsule of ginger powder which was dried in a dark condition at room temperature (processed in Iran, unknown constituents)
Protocol 1: 50 mg TID × 5 days (2 days prior to day 3 of period)
Protocol 2: 50 mg TID × 3 days (first 3 days of a period)
PlaceboPain severity (VAS)
Pain duration (hours in pain)
(i) Pain severity was significantly reduced with ginger compared to placebo for both Protocol 1 and Protocol 2.
(ii) Pain duration was significantly reduced with ginger compared to placebo for Protocol 1 but not for Protocol 2.
GI side effects were reported in 5.1% of ginger group (heartburn) and 8.7% of the placebo group (nausea)

Kashefi et al., 2014 [24](i) High school students (15–18 yo) in Iran
(ii) Moderate to severe dysmenorrhea
(iii) With primary dysmenorrhea
(iv) Not on OCPs, hormonal meds, or analgesics
4745 Placebo
54 Zinc
Capsule of ginger powder (unknown origin and constituents)
250 mg TID × 4 days for 2 menstrual cycles
Placebo
Zinc 220 mg 3 times/day for 4 days
Pain severity (VAS)(i) Compared with the placebo group, the ginger group and zinc group reported more symptom improvement for both Cycle 1 and Cycle 2. Ginger group reported headache (2.1% in Cycle 1, 2.2% in Cycle 2) and heartburn (2.1% in Cycle 1 and 4.4% in Cycle 2)
No significant difference in adverse effects among the groups

Ozgoli et al., 2009 [14](i) College students (>18 yo) in Iran living in the dorm
(ii) Having moderate to severe dysmenorrhea
(iii) With primary dysmenorrhea
(iv) Not on OCPs
(v) BMI between 19 and 36
5050 Ibuprofen
50 Mefenamic acid
Capsule of ginger powder (Zintoma an Iranian brand, unknown constituents)
250 mg QID × 3 days
NSAIDS
Ibuprofen 400 mg 4 times day for 3 days
Mefenamic acid 250 mg 4 times day for 3 days
Pain severity assessed by the VMS(i) No significant difference in pain severity was found between ginger, ibuprofen, and mefenamic acid. None reported

Shirvani et al., 2015 [23](i) College students (>18 yo) in Iran living in the dorms
(ii) With primary dysmenorrhea
(iii) Having moderate to severe dysmenorrhea
(iv) Not using IUD or OCs
6161Capsule of ginger powder (Zintoma, an Iranian brand with unknown constituents)
250 mg QID until pain relieved
Mefenamic acid
250 mg 3 times per day until pain was relieved
Worst pain severity assessed by VAS
Pain duration (days in pain)
(i) No significant difference in pain severity was found between ginger and mefenamic
(ii) No significant difference in pain duration was found between ginger and mefenamic acid.
None reported

Halder, 2012 [25](i) Nursing students in India
(ii) With primary or secondary dysmenorrhea
(iii) Not on IUD or taking OCPs
2525 PMR
25 Control group
Capsule of ginger powder (unknown origin and constituents)
1000 mg BID × 3 days
PMR once/day × 3 days
Control (little information provided)
Severity of dysmenorrhea symptoms (five point scale)(i) Both ginger and PMR were more effective than control in managing dysmenorrhea symptoms, but ginger was more effective than PMR for cramping, colicky pain in lower abdominal pain, nausea, and diarrhea. None reported

TID: three times a day.
VAS: visual analogue scale (0–10 cm).
yo: years old.
BMI: body mass index.
GI: gastrointestinal.
OCPs: oral contraceptive pills.
QID: four times a day.
NSAIDs: nonsteroidal anti-inflammatory drug.
VMS: verbal multidimensional scoring system.
IUD: intrauterine device.
PMR: progressive muscle relaxation.
BID: twice a day.