Numerous experimental and clinical observations have established the role of hypertonic duodenal dyskinesia in the etiology of duodenogastric reflux and delayed emptying of the stomach. The original procedure proposed, section of the duodenal muscle fibres, demonstrated a relative hypotonia of the viscera and maintenance of antropyloroduodenal coordination. The present study confirms the effects of extramucosal duodenal myotomy after short- and long-term follow-up in dogs: reduction in gastric emptying time, absence of duodenal stagnation, and lack of morphological changes in the viscera. Unfavorable in duodenogastric reflux, it has favorable effects, on the contrary, on gastric emptying and antral function.