Recent double blind studies have shown some benefit of borage oil in treatment of rheumatoid arthritis. Tumor necrosis factor-alpha has been shown to be a central mediator of inflammatory and joint destructive processes in rheumatoid arthritis. In this paper, evidence from published research is reviewed that indicates gamma linolenic acid component of borage oil increases prostaglandin E levels that increase cAMP levels that in turn suppress tumor necrosis factor-alpha synthesis. If this biochemical path of borage oil is correct then (1) concomitant non-steroidal anti-inflammatory drug use would tend to undermine borage oil effects, and (2) borage oil would be contraindicated in pregnancy given the teratogenic and labor inducing effects of prostaglandin E agonists.