Natural products with immunomodulatory effects are widely used in the treatment of many diseases, including autoimmune diseases, as well as cancer and inflammatory diseases. They have attracted great interest as therapeutic agents in recent decades because they offer inexpensive and less toxic products than synthetic chemotherapy agents. Immunomodulators are substances that have the ability to improve or suppress the host's defense response, which can be used for prevention and in combination with other treatments. The anticancer effects of these immunomodulators result from their anti-inflammatory, antioxidant and apoptosis-inducing, anti-angiogenic and anti-metastatic effects. In addition to preventing tumor growth and proliferation, these natural immunomodulators, such as curcumin and Vinca, can also be used as a preventive treatment against cancer. In contrast, immunostimulants can induce and activate humoral and cell-mediated immune responses against the tumor, which facilitates the recognition and destruction of a pre-existing tumor.