Abstract: AIM To observe the effect of shuangdan oral liquid (SOL) on cardiac stem cells (CSCs) cultured in vitro. METHODS CSCs were isolated and cultured. The second generation CSCs were cultured with different concentrations of SOL (control group; 1×10-1 mol/L; 1×10-2 mol/L; 1×10-3 mol/L; 1×10-4 mol/L; 1×10-5 mol/L; 1×10-6 mol/L) and after 24 h and 48 h, the influence of SOL on CSCs was detected by MTT assay. CSCs were cultured with 10-2 mol/L SOL and after 24 h the content of c-kit+ CD45 cells was measured by flow cytometry. RESULTS Fibroblast-like cells distributed from tissue pieces 3 days after myocardial tissue digestion and small, round, bright cells were observed on the fibroblast layer around the tissue. After subculture, cells showed uniform shuttle type and cardiac stem cells formed “sun-like” colonies under inverted microscope. Compared with the control group, cells cultured in SOL grew and proliferated rapidly. When the concentration of SOL exceeded 1×10-3 mol/L, cardiac stem cells proliferated more significantly (P<0.05). FCM showed that c-kit+/CD45 cells reached 0.976% when cultured in SOL (1×10-2 mol/L) for 24 h, significantly higher than the 0.301% of the cells in normal culture (P<0.01). CONCLUSION The c-kit cardiac stem cells can be successfully obtained from the cardiac tissue of New Zealand rats by enzymatic digestion. SOL promotes cardiac stem cell growth and proliferation in vitro.