Carbon dots (CDs) are a class of carbon-based nanomaterials undergoing rapid development with broad potential applications across diverse biomedical fields. These materials are highly attractive for diagnostics, therapeutics, and nanomedicine due to their remarkable optical and physicochemical properties, including photoluminescence, biocompatibility, and aqueous dispersibility. CDs can be synthesized using various techniques, ranging from top-down to bottom-up approaches. Among these, biogenic synthesis, utilizing natural sources and waste materials, presents an eco-friendly and sustainable alternative. CDs have exhibited considerable promise in diagnostics, especially with bioimaging and biosensing, providing both high sensitivity and precise identification. CDs are presently being investigated in the pharmaceutical sector for their potential applications in cancer and infection treatment, as well as in photodynamic and thermal therapies. The advancement of CD composites, through enhanced functionality and broader application, facilitates novel research in nanomedicine. This article highlights the advantages of CDs, focusing on their structural properties, classification, and versatility in synthesis methods. Furthermore, the safety and toxicity profiles of CDs are critically analyzed. In conclusion, the innocuity, adaptability, and multifunctionality of CDs position them as a cornerstone in the advancement of nanotechnology and biomedical applications. With their broad applicability and promising potential, CDs stand poised to drive significant innovation across diagnostics, therapeutics, and other domains, heralding a new era in nanomedicine and sustainable material development.