Implications for practice  

Oral borage oil and evening primrose oil lack effect on eczema; improvement was similar to respective placebos used in trials. Oral BO and EPO are not effective treatments for eczema.
In these studies, along with the placebos, EPO and BO have the same, fairly common, mild, transient adverse effects, which are mainly gastrointestinal.
The short-term studies included here do not examine possible adverse effects of long-term use of EPO or BO. A case report warned that if EPO is taken for a prolonged period of time (more than one year), there is a potential risk of inflammation, thrombosis, and immunosuppression; another study found that EPO may increase bleeding for people on Coumadin® (warfarin) medication.

Implications for research 

Noting that the confidence intervals between active and placebo treatment are narrow, to exclude the possibility of any clinically useful difference, we concluded that further studies on EPO or BO for eczema would be hard to justify.
This review does not provide information about long-term use of these products.
Evening primrose oil is effective in atopic dermatitis: a randomized placebo-controlled trial.
Atopic dermatitis (AD) is a chronic, relapsing, itchy dermatosis of multifactorial origin, which commonly starts in childhood. Defective metabolism of essential fatty acids leading to relative dominance of pro-inflammatory prostaglandins (PGE2 and PGF2) has been reported as an important factor in the pathogenesis of AD. Evening primrose oil (EPO) as a source of gamma-linolenic acid (GLA) has been of interest in the management of AD.
                To evaluate the efficacy and safety of EPO in atopic dermatitis in our patients.
                Consecutive new out-patient department (OPD) patients of a referral hospital in Kolkata clinically diagnosed as having AD were randomly allocated to two groups. To the first group, evening primrose oil was supplied as 500-mg oval clear unmarked capsules, while placebo capsules identical in appearance and containing 300 mg of sunflower oil were given to the other group. Treatment continued for a period of 5 months. With pre-designed scoring system (based on four major parameters: extent, intensity, itching, and dryness), clinical evaluation was done at baseline and subsequent monthly visits. Data of the first 25 patients from each group who completed the 5 months of trial were compiled and analyzed.
                At the end of the fifth month, 24 (96%) patients of EPO group and 8 (32%) patients of placebo group showed improvement. There was significant difference in outcome of treatment between two groups (P<0.00001). No significant adverse effect was reported by any patient/guardian at any point of assessment.
                Evening primrose oil is a safe and effective medicine in management of AD. However, since not all researchers across the world have found the same good result, further large trials on Indian patients are needed.