We have studied tissue zinc levels and zinc balance in isocalorically pair-fed weanling rats on ZD liquid diets (0.9 microgram of zinc per milliliter of diet). Tissues were analyzed for zinc levels at weekly intervals while the animals were on the diets. The experimental animals were fed a ZDE diet, whereas sucrose was isocalorically substituted for alcohol in the pair-fed controls. After 1 week on ethanol feeding, the zinc content (microgram/gm wet weight) of the testes of the ethanol-fed rats was significantly lower than of the controls (p less than 0.001). After 2 weeks of ethanol, ethanol-fed animals also showed significantly lower zinc content in liver, hair, spleen, and kidneys (p less than 0.02) than their pair-fed controls. The zinc levels of the experimental animals in all tissues after 3 and 4 weeks of ethanol feeding were significantly lower (p less than 0.001) than that of the pair-fed controls with the exception of bone. Urinary and fecal zinc excretions of the ethanol-fed rats were significantly higher than that of the controls. Cumulative mean +/- S.D. fecal zinc excretions (microgram/28 days) were 1557 +/- 160 among the ethanol-fed animals vs. 730 +/- 150 among controls, p less than 0.01. Ethanol resulted in a mean negative zinc balance of 520 micrograms over 28 days, whereas controls showed a positive cumulative zinc balance of 300 micrograms. Thus ethanol ingestion resulted in negative zinc balance and decreased zinc concentrations of most tissues as compared to pair-fed controls.