Nine patients with severe symptoms of diffuse esophageal spasm and lower esophageal sphincter dysfunction who were unresponsive to medical therapy and bougienage dilatation were treated by forceful pneumatic dilatation. Treatment with pneumatic dilatation in eight of the nine patients produced a marked improvement in dysphagia and regurgitation (average follow-up of 37.4 months). Esophageal motility performed up to three years (average 12.4 months) after clinically successful pneumatic dilatation revealed a decrease in lower esophageal sphincter pressure from 34.0±4.0 mmHg (mean ± standard error) to 19.2±2.7 mm Hg (P<0.01). there="" were="" no="" significant="" changes="" in="" either="" the="" percentage="" of="" lower="" esophageal="" sphincter="" relaxation="" or="" the="" type="" of="" esophageal="" motor="" pattern.="" we="" conclude="" from="" this="" study="" that="" pneumatic="" dilatation="" is="" an="" effective="" form="" of="" therapy="" for="" a="" select="" group="" of="" patients="" with="" severe="" symptomatic="" diffuse="" esophageal="" spasm="" with="" lower="" esophageal="" sphincter="" dysfunction="" who="" are="" unresponsive="" to="" conventional="" medical="">