The efficacy of Astragalus membranaceus (AM) oral liquor combined with routine therapy and routine therapy alone on T-lymphocyte subsets of peripheral blood in viral myocarditis patients have been studied. The results showed that the T-lymphocyte subsets profile and OKT4/OKT8 ratio of peripheral blood were significantly lower in viral myocarditis patients than that in healthy control (P < 0.05, 0.01). Routine therapy combined with AM could significantly enhance OKT3, OKT4 and OKT4/OKT8 ratio in the above-mentioned patients (P < 0.05, 0.01). The possible pharmacodynamic mechanism of improved cell immunity in viral myocarditis patients by combining routine therapy with AM was discussed.