Changes in the plasma levels and urinary excretion of zinc have been studied in a series of adult patients receiving intravenous alimentation. Urinary zinc loss may be very high in this group, but serious plasma depletion does not occur unless there is a concomitant phase of sustained anabolism in the absence of significant exogenous intake. A syndrome of acute zinc deficiency is described consisting of diarrhea, mental apathy and depression, a moist eczematoid dermatitis, most severe in the perioral area and alopecia. The response to intravenous zinc therapy is very striking although alopecia is slower to develop and complete hair regrowth is correspondingly delayed.