Rhodiola quadrifida (Rq) roots and rhizomes are traditionally used in Asia as a tonic, adaptogen, antidepressant and anti-inflammatory drug. The aim of this work was to study the in vivo effect of aqueous and 50% hydro-alcoholic extracts of Rq rhizomes on some parameters of cellular immunity in mice and rats. The metabolic activity of blood phagocyting cells was determined based on the measurement of intracellular respiratory burst after stimulation by PMA in RBA test. Potential bactericidal activity of phagocyting cells was determined in isolated blood leukocytes stimulated with killed microorganisms, according to the PKA test. Proliferative response of lymphocytes stimulated by mitogen concanavaline A (ConA) or lipopolysaccharide (LPS) were determined by MTT assay. Both extracts stimulated granulocytes activity in vitro and increased lymphocyte response to mitogens. The ability of parental strain mice lymphocytes to induce local cutaneous graft-versus-host reaction (GVH) in F1 hybrids was stimulated by 50% hydro-alcoholic extract only.