Based on a common belief, herbal medicine with the least possible side effects should be the center of attention in cancer care; however, in many cases they have not been properly studied with reliable clinical trials in human subjects. In this review, it was attempted to identify the available evidence on the use and clinical effects of herbs in cancer care. The research consists of two major parts including immunomodulator and chemopreventive herbal compounds whose mechanism, biological response, anticancer element of extract and related benefits were completely studied. Also, the safety of herbal anticancer compounds was discussed. Although the use of herbal medicines in treating cancer shows less chemotherapy-induced, toxicity, more researches are required to reach their full therapeutic potentials.