Roberts 1995.

Methods	Random assignment to 2 treatment groups.
Participants	28 lactating women with breast engorgement. Inpatients recruited from 2 hospitals in Darwin, Australia, usually on the 3rd day postpartum. Inclusion criteria: lactation and engorgement defined as ˝hard, very warm, painful breasts, with difficulty feeding", according to the professional judgment of the midwives caring for them. Exclusion criteria: Aboriginal women.
Interventions	Group 1: chilled cabbage leaves were placed on the right breast and room temperature cabbage leaves were placed on the left breast. Group 2: cabbage leaves placed in reverse order. Cabbage leaves applied between feedings and left on for 2 hours. Cabbage leaves, from common green cabbages (Brassica oleracea), were prepared by stripping out the large vein, cutting a hole for the nipple, rinsing, and chilling or leaving at room temperature.
Outcomes	Pain: pre‐treatment measurement; post‐treatment measurement 2 hours later.
Notes	This was a convenience sample of lactating women with breast engorgement. All women had both treatments and analyses were for individual breasts rather than for women. As breasts are not independent, results are very difficult to interpret. Pre‐test assessments were for 28 women whereas post‐test assessments were for 56 breasts. Data were not in a form in which we were able to enter them into data tables.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described.
Allocation concealment (selection bias)	Unclear risk	The authors did not state how allocation concealment was done.
Blinding (performance bias and detection bias) Women	High risk	Blinding of participants was not feasible. All women had both treatments ‐ 1 on each breast and the treatments were not identical as 1 was cold and 1 was room temperature cabbage leaves.
Blinding (performance bias and detection bias) Clinical staff	High risk	Blinding was not feasible as women either received cold or room temperature cabbage leaves.
Blinding of outcome assessment (detection bias)	High risk	Women were assessing their breast on a visual analogue scale and midwives were supervising.
Incomplete outcome data (attrition bias) All outcomes	Low risk	The authors reported on all participants included in the study.
Selective reporting (reporting bias)	Low risk	The authors reported on all outcomes.
Other bias	High risk	Analysis was by breast rather than by women. Breast are unlikely to be independent, especially in terms of outcomes reported in this study. As mentioned in McLachlan 1991, when a visual analogue scale was used, it was not always easy for women to make a clear distinction between the left and the right breast.