The present invention relates to a conditioned medium (CM) which is obtained by culturing, in a liquid culture medium, placental mesenchymal stem cells isolated from the placental tissue of pregnant women who not affected by preeclampsia. The conditioned medium of the present invention includes at least IL-6, IL-8 and MCP-1 proteins. The conditioned medium of the present invention is effective for the therapeutic treatment of preeclampsia.
