Cancer is the second leading cause of death and morbidity in the world among noncommunicable diseases after cardiovascular ailments. With the advancement in science and research, a number of therapies have been developed to treat cancer, including chemotherapy, radiotherapy and immunotherapy. Chemo and radiotherapy have been in use since the last two decades, however these are not devoid of their own intrinsic problems, such as myelotoxicity, cardiotoxicity, nephrotoxicity, neurotoxicity and immunosuppression. Hence, there is an urgent need to develop alternative methods for the treatment of cancer. An increase in the cases of various cancers has encouraged the researchers to discover novel, more effective drugs from plant sources. In this review, fifteen medicinal plants alongside their products with anticancer effects will be introduced and discussed, as well as the most important plant compounds responsible for the anticancer activity of the plant. Several phenolic and alkaloid compounds have been demonstrated to have anticancer effects on various types of cancers. The most fundamental and efficient role exhibited by these secondary plant metabolites against cancer involves removing free radicals and antioxidant effects, induction of apoptosis, cell cycle arrest and inhibition of angiogenesis. Moreover, recent studies have shown that plants and their metabolites may provide an alternative to the existing approaches, including chemotherapies and radiotherapies, in the treatment of cancer. In this review, a brief overview of important secondary metabolites having anticancer activity will be given, along with the major molecular mechanisms involved in the disease. In addition to this, recent advances in secondary metabolites from various medicinal plants in the prevention and treatment of cancer will be explored.