Carbon dots (C-dots) are promising nanomaterials with low toxicity, ease of synthesis, high dispersibility in aqueous conditions, and good biocompatibility, making them suitable for antibacterial, antifungal, antiviral, and anticancer applications. This review discusses the structure, classification, synthesis methods, and biological activities of C-dots. C-dots are typically core-shell structures with a carbon core and polymer shell, and their properties can be tuned through surface functionalization. They exhibit unique optical properties, such as fluorescence, and can be used in biomedical imaging and therapy. C-dots have been shown to have antibacterial, antifungal, and antiviral activities, with their effectiveness influenced by factors such as surface charge, size, and functional groups. They can also exhibit anticancer activity by inducing oxidative stress, disrupting cell membranes, and inhibiting DNA replication. C-dots are being explored as potential carriers for drug delivery, with their ability to cross biological barriers and target specific cells. However, their biocompatibility and toxicity need further investigation, particularly in vivo. The review highlights the potential of C-dots as a versatile platform for biomedical applications, including antimicrobial, antiviral, and anticancer therapies.Carbon dots (C-dots) are promising nanomaterials with low toxicity, ease of synthesis, high dispersibility in aqueous conditions, and good biocompatibility, making them suitable for antibacterial, antifungal, antiviral, and anticancer applications. This review discusses the structure, classification, synthesis methods, and biological activities of C-dots. C-dots are typically core-shell structures with a carbon core and polymer shell, and their properties can be tuned through surface functionalization. They exhibit unique optical properties, such as fluorescence, and can be used in biomedical imaging and therapy. C-dots have been shown to have antibacterial, antifungal, and antiviral activities, with their effectiveness influenced by factors such as surface charge, size, and functional groups. They can also exhibit anticancer activity by inducing oxidative stress, disrupting cell membranes, and inhibiting DNA replication. C-dots are being explored as potential carriers for drug delivery, with their ability to cross biological barriers and target specific cells. However, their biocompatibility and toxicity need further investigation, particularly in vivo. The review highlights the potential of C-dots as a versatile platform for biomedical applications, including antimicrobial, antiviral, and anticancer therapies.