Over the past 30 years human magnesium (Mg) deficiency has become an accepted fact in most medical circles. Our index patient had striking neurological manifestations including generalized tremulousness, grimaces and fibrillary twitches of facial muscles, athetoid and choreiform movements of upper extremities, dysphagia, inability to speak, repeated convulsions, and confusion. She had received glucose in water and saline intravenously for several months. A patient with chronic alcoholism was noted to have almost identical symptoms and signs as the index patient. He also responded dramatically to MgSO4 injections. This resulted in a series of studies on patients with chronic alcoholism. The evidence of Mg deficiency in alcoholism includes the following: significant hypomagnesemia, strongly positive Mg balance during recovery, significant decrease in muscle Mg, a deficit of total exchangeable 28Mg quantitatively similar to deficit by balance studies, often a dramatic response of symptoms to therapy with Mg, and diuresis of Mg produced by ingestion of alcohol. Lipolysis with high levels of long-chain free fatty acids (FFA) occurs in withdrawal of alcohol in chronic alcoholism, withdrawal of certain addictive drugs, after trauma, surgery, administration of adrenergic compounds or theophylline, exposure to cold, and an adverse environment as in grass staggers. Concentrations of Mg fall when FFA increase in all of the above circumstances. This phenomenon has wide implications in health and disease. Better awareness of Mg deficiency in a wide variety of clinical conditions will result in life-saving treatment and less morbidity of other patients.