Carbon-based nanomaterials (NMs) are a specific class of materials used in biomedical applications, such as the delivery of therapeutics, biomedical imaging, biosensors, tissue engineering, and genetic engineering. Carbon-based NMs are interesting tools with specific qualities, including strong mechanical structure, good conductivity, appealing visual qualities and great chemical versatility. Among these carbon-based NMs, graphene and carbon nanotubes (CNTs) are of great biological importance. In this paper, we discuss about graphene, CNTs, fullerene and carbon quantum dots (CQDs), the structure, properties, toxicity, mechanism of action and applications in cancer treatment and diagnosis. Graphene, fullerene, CNTs and CQDs are allotropic forms of carbon. The circle of biomedical engineering is increasing daily, and in recent years, carbon-based NMs have played a vital role as biomaterials. Carbon-based NMs attracted the attention of a wide range of researchers due to their multifunctional properties. In this paper, we discuss the function of carbon-based NMs in the detection and treatment of cancer and explore their role in controlling tumor-causing cells and damaging cancer-causing cells. If we use their derivatives as a source for cancer treatment and diagnosis, we can cease tumor growth to a tremendous level.