Supplementation of fish oil alleviates joint pain in patients with auto-immune disease (17). Inhibition of pro-inflammatory cytokines (which induce both pain and depression-like symptoms) by ω3 PUFAs may underlie the benefit conferred by fish oil consumption (18). Interestingly, RBC ω3 PUFA content is lower in patients with Systemic Lupus Erythematosus (SLE, refs 19,20) and chronic fatigue syndrome (CFS, ref 21), compared to healthy controls. SLE and CFS are considered to be auto-immune and functional disorders, respectively, but both share characteristics of fibromyalgia: a higher incidence in women, increased depressive co-morbidity and the frequent presence of fibromyalgia-like symptoms (22,23). However, the ω3 PUFA status of fibromyalgia patients has not been assessed.