Oral inositol has been reported to have antidepressant and antipanic properties in humans. Inositol enters the brain poorly and high doses are required. Natural uptake processes and specific transporters are involved. We here report that intraperitoneally administered inositol is taken up differently by various brain areas and that brain areas have different baseline inositol levels. These effects could be important in understanding the differential effects of lithium-induced lowering of inositol and of behavioral effects of exogenous inositol.