Doxorubicin and Trifolium pratense L. (Red clover) extract synergistically inhibited the metastasis of 4T1 to the lungs and brain by reducing cytokines (IL‐6 and IL‐8) and genes (SIRT‐1 and MMP‐2) associated with metastasis in tumor‐bearing BALB/c mice. Here, MMP2 is linked to neoplasm.