Twenty-four control and 104 stinging insect-allergic patients were tested in this multicenter study, which compared the utility of individual venom and whole body extract (WBE) preparations for diagnosis. This study indicates that venom skin testing is more specific and more reliable than is testing with WBE. There was a high rate of WBE skin-test reactivity among controls. False-positive skin testing with venom was not a problem at concentrations of 1 microgram/ml or less. Only one mild and easily treated adverse reaction occurred in this study.