The aim of this study was to investigate the inhibitory effect of heat-killed () and live on benign prostatic hyperplasia (BPH). The BPH rat model was established by administering male rats with testosterone propionate (TP, 5 mg/kg, in corn oil) via subcutaneous injections daily for four weeks after castration. The rats were divided into five groups: Con, corn oil-injected (s.c.) + DW administration; BPH, TP (5 mg/kg, s.c.) + DW administration; BPH+K_EF, TP (5 mg/kg, s.c.) + heat-killed (7.5 × 10 CFU/g, 2.21 mg/kg) administration; BPH+L_EF, TP (5 mg/kg, s.c.) + live (1 × 10 CFU/g, 166 mg/kg) administration; BPH+Fi, TP (5 mg/kg, s.c.) + finasteride (1 mg/kg) administration. In both of BPH+K_EF and BPH+L_EF groups, the prostate weight decreased and histological changes due to TP treatment recovered to the level of the Con group. The both of groups showed regulation of androgen-signaling factors, growth factors, and apoptosis-related factors in prostate tissue. exhibited inhibitory effect on benign prostatic hyperplasia, and even heat-killed showed similar efficacy to the live cells in the BPH rat model. This is the first investigation for the effect of heat-killed and live on BPH, suggests that heat-killed might be a candidate for the food additives in various foods regardless of heat processing.