Lactobacillus acidophilus may have a role in the treatment of chronic fatigue syndrome, particularly when incorporated into 'floating' alginate beads. In a rat model of chronic fatigue syndrome induced by physical fatigue (swimming), L. acidophilus (free or delivered in beads) had a significant and beneficial effect on immobility and postswim fatigue time; levels of oxidonitrosative stress and tumor necrosis factor were also attenuated and spleen and thymus size restored.