Abstract Levels of IgE antibody to fire ant whole body extract (FA-WBE) and fire ant venom (FAV) were evaluated in 60 patients with clinical histories of fire ant sting hypersensitivity and 11 frequently stung individuals without significant clinical reactivity to fire ant. An overlap of levels of IgE antibody to FA-WBE and FAV was seen between groups of patients with increasingly severe clinical reactivity; however, the group mean IgE antibody level of patients without significant clinical reactivity differed markedly from the group means of patients with more severe clinical reactivity (p