<p>Carrageenan, a natural polysaccharide derived from red algae, has garnered significant attention for its versatile applications in biomedical, pharmaceutical, and material sciences because of its inherent biological and gelling nature. Moreover, its intrinsic properties, including gel-forming ability, biocompatibility, and tunable viscosity, make it a valuable material for drug delivery, tissue engineering, and food technology. However, these properties can be further enhanced or tailored through chemical and structural modifications per the requirements of biomedicine. This review explores various modifications of carrageenan, such as functional and ionic modifications, that alter its physiological and biomedical properties. Common changes in hydrophobicity were found through the addition of extra carbon chains and functional groups; moreover, ionic changes also affected hydrophobicity and cancer cell selectivity in the case of barium ions, which were analysed through the encapsulation of a water-insoluble drug. The conductivity was also enhanced by ionic changes as well as the addition of aromatic groups to carrageenan, which could be utilized for ionic moments in tissue engineering and ion-linked targeted drug delivery. Overall, all of these modifications were crucial for resolving the limitations of the parent polymer (toxicity, conductivity and excessive hydrophilicity), expanding its range of possible uses and expanding its use in targeted drug delivery, cancer therapy, wound healing, and smart material development. This review delves into the underlying mechanisms of these modifications and highlights their impact on the biomedical and material science applications of carrageenan, providing a pathway for future innovations in this field.</p>