The efficacy of the Chinese herbal therapy (Zemaphyte) has been well established as a treatment for atopic eczema (AE) in clinical trials. The purpose of this study was to probe the immunological changes that occurred when patients were treated with the herbs for a period of 8 weeks. This treatment decreased serum IgE complexes (p less than 0.05) but did not affect total serum IgE or CD23 expression on peripheral blood monocytes. Peripheral blood mononuclear cells from patients before and after treatment were cultured overnight with interleukin 4 and the ability of this cytokine to induce CD23 on monocytes from treated patients was found to be significantly diminished (p less than 0.01). Soluble interleukin 2 receptor and soluble vascular cell adhesion molecule were both raised in the serum of AE patients compared to control individuals. Both these parameters were decreased following treatment (p less than 0.05). All these changes coincided with improvement in erythema and surface damage scores. There was no alteration in soluble intracellular adhesion molecule or soluble CD23. The results of these investigations would suggest that this herbal treatment has the ability to target various immunological parameters which may be involved in the pathogenesis of AE.