We administered intravenous ergonovine maleate to 14 patients with chest pain resembling angina pectoris and to four healthy volunteers. Five of the patients experienced their typical chest pain after ergonovine, and manometric signs of esophageal spasm also developed. The remaining nine patients and the four volunteers did not experience chest pain, but all subjects except one had some symptomatic response to ergonovine, including chest warmth or heaviness, headache, mild choking sensation, facial numbness, flushing, or nausea. Two of the nine patients and one of the four volunteers developed manometric signs of esophageal spasm after ergonovine but experienced no chest pain. Intravenous ergonovine may be useful to identify esophageal spasm in selected patients with chest pain who have normal coronary arteries or in whom coronary artery disease is insufficient to explain symptoms. However, we believe that the potential risks of ergonovine do not justify its routine use as a provocative agent for esophageal spasm.