The hypothalamic proteomes were analyzed 1 and 6 hr after an intraperitoneal injection of lithium chloride or sodium chloride (0.15 M, 12 ml/kg). Results showed that expression of 14 and 32 proteomes was increased consistently by 1 hr and 6 hr of lithium treatment, respectively. Among them, tentative implications of glial fibrillary acidic protein, receptor-type protein tyrosine phosphatase, spectrin, and glutamate dehydrogenase in the lithium-induced activation of the hypothalamic-pituitary-adrenal axis, and conditioned taste aversion have been discussed. The proteomes listed in this study will provide, at least, a new insight to understand the molecular mechanism of lithium's action in the brain.