The aim of this paper is to describe and discuss, on the basis of the available literature, the case of an old female patient, admitted to our university hospital because of a severe dysphagia for solid foods, in whom laboratory data showed a marked hypomagnesemia. She reported a long history (20 years) of allergic bronchial asthma treated with theophylline. Esophagography evidenced a disorder of esophagus motility with diffuse multiple spasm, reminiscent of the 'corkscrew esophagus'. A link with the severe hypomagnesemia (Mg 1.1 mEq/l, normal range 1.6-2.1) was suspected, and a therapy with oral pidolate of Mg (1.5 g/twice a day) was started and continued for 4 months. This was associated with a slow progressive normalization of the Mg plasma level and reverted radiographic esophageal findings with disappearance of dysphagia. Mg is an important element for health and disease, and today Mg deficiency in man has become an accepted medical problem which might complicate many diseases. Neuromuscular disorders, as laryngeal spasm, are recognized complications of hypomagnesemia, but until now only 1 case of motor esophageal disorder associated with a low Mg plasma level was briefly reported in the literature, even if dysphagia is generally included in the symptomatological pattern of hypomagnesemia. Our observation of a severe form of esophageal spasm, associated with hypomagnesemia, in an aged female patient underlines the pathophysiological meaning of the plasma Mg level and suggests the need for routine Mg determination in the clinical setting.