Protective properties of a new enterosorbent noolith (lithium ions immobilized on mineral matrix) were studied in C57Bl/6J mice predisposed to depression caused by intermale confrontations. The drug was administered daily for 15 days after the 5th confrontation and then the animals were tested in the forced swimming test. The number of specific(3)H-8-OH-DPAT binding sites in 3 brain regions was determined. It is shown that noolith produced an antidepressive effect manifested in decreased immobility time in the Porsolt test. Moreover, noolith reduced the number of 1A-serotonin receptors in the frontal cortex and hypothalamus. It is concluded that noolith possesses protective properties.