Assessment of dilation methods in achalasia: large diameter mercury bougienage followed by pneumatic dilation as needed. In a retrospective study, 33 achalasia patients were treated with dilation therapy using large diameter mercury bougienage (mean, 56 French) and/or pneumatic balloon dilation. Mean follow-up time was 35 months. Mercury bougienage, performed in 20 patients, was successful in 10 (50%) with no complications. Pneumatic dilation was performed as initial therapy or in those having failed previous pharmacologic therapy and/or bougienage. A successful response was achieved in 19 of 23 patients (83%), with a 3.2% complication rate. In addition, in four patients with eventual recurrence of symptoms after initial pneumatic dilation, bougienage was used as a successful alternative to repeat pneumatic treatment. The combined efficacy of both forms of dilation was 88% with a complication rate of 1.4%. These data indicate that mercury bougienage should be considered initial therapy for achalasia in view of its simplicity, safety, and acceptable efficacy, followed by pneumatic dilation if bougienage is unsuccessful. Bougienage also may be considered if eventual recurrent symptoms develop after initially successful pneumatic dilation. Surgery should be utilized only if dilation therapy fails to achieve a satisfactory response. 