A series of 61 cases of a nutritional myelopathic syndrome is described. Two autopsies are described in detail, and the main pathological feature in both is degeneration of the lateral pyramidal tracts. Four stages of this nutritional syndrome are recognized, commencing with mild hyperreflexia and often ending with total quadriplegia. Sensory signs are negligible. Mental confusion and symptoms and signs of avitaminosis are commonly associated with the neurological picture. A low intake of protein, fats, and vitamins, and often excessive alcohol intake, can be implicated in most cases. However, no evidence of the pea Lathyrus sativus is forthcoming as an etiological agent. Evidence of liver damage often was apparent, but all other investigations were essentially negative. The response to all forms of therapy is poor, except for temporary improvement in the earlier stages and remission of most of the psychic changes.