DMH-1 is a second-generation small molecule BMP inhibitor based on dorsomorphin. DMH-1 effectively inhibits the bone morphogenic protein (BMP) ALK2 receptor (IC50 = 108 nM). Treatment with DMH1 reduced lung metastasis and the tumors were less proliferative and more apoptotic. In the surrounding tumor microenvironment, treatment with DMH1 altered fibroblasts, lymphatic vessels and macrophages to be less tumor promoting. These results indicate that inhibition of BMP signaling may successfully target both the tumor and the surrounding microenvironment to reduce tumor burden and metastasis.