This invention relates to methods and compositions for treating carcinoid syndrome and other adverse symptoms associated with tumor-producing neuroendocrine tumors, said methods comprising administering a therapeutically effective amount of a vascular disrupting agent, or a pharmaceutically acceptable salt thereof, to a subject having a hormone producing neuroendocrine tumor. In preferred implementations, the vascular disrupting agent is combretastatin A-4 phosphate, combretastatin A-1 diphosphate, or a pharmaceutical acceptable salt thereof.