The effects of the volatile oil ofMosla Chinensis Maxim(MCMVO) onimmune responses in mice were stu-died.When mice immunized with SRBC were fed with MCMVO (190mg/kg/d),the specific antibody levelin serum and the activity of antibo-dy forming cells increased.on nons-pecific immunity,MCMVO also acti-viated alternative complement path-way and increased the activity oflysozyme in serum.MCMVO alsoenhanced peripheral ANAE~+ lympho-cytes ratio in comparison with cont-rol.MCMVO could also significantlyincreased the spleen weightof young mice.The resultsmentioned above suggestedthat MCMVO could raise thenonspecific and specific immunity.It might be expected that MCMVOcould be useful in precaution andtreatment of infectious diseases.