The present invention provides for the use of a dimeric phthalide compound, the dimeric phthalide compound has broad anti-tumor activity, can directly inhibit the proliferation of tumor cells and induce cell death, but also indirectly inhibit the development of tumors by suppressing neovascularization. And further, the dimeric phthalide compound can be used alone or in combination to treat cancer, as well as in combination with chemotherapeutics to increase the efficacy of chemotherapeutics and decrease the toxicity of chemotherapeutics.
