Peripheral blood mononuclear cells were isolated before and after the Spirulina feeding and levels of cytokines (interleukin-4 (IL-4), interferon-γ(IFN-γ) and interleukin-2), which are important in regulating immunoglobulin (Ig)E-mediated allergy, were measured. The study showed that high dose of Spirulina significantly reduced IL-4 levels by 32%, demonstrating the protective effects of this microalga toward allergic rhinitis.