Natural polymers are derived from agriculture, forestry and marine products or isolated from their wastes. The use of biopolymers, as opposed to synthetic polymers, offers significant advantages by reducing environmental impact and minimizing potential health risks. This study focuses on three polysaccharides (Cellulose, starch, and chitosan) and one protein (Zein), for applications in medicine and healthcare. These biopolymers and some of their derivatives are well-suited for medicine and healthcare applications, due to their several key properties as follows: (1) They are derived from renewable resources, and are environmentally friendly biomaterials, making them promising materials for sustainable medical uses; (2) These biopolymers possess excellent film- and fiber-forming capabilities, which are essential in biomedical engineering and drug delivery systems; (3) Their hydrophilic nature provide a range of surface functional groups that can bind to bioactive compounds, drugs, target organs, and nutritional components, enhancing their stability and effectiveness; (4) The degree of hydrophilicity varies among different biopolymers, enabling a wide range of chemical modifications and expanding their potential applications across medicine, healthcare, and nutrition; (5) The nano-sized biopolymers have demonstrated superior properties and performances compared to their conventional counterparts, offering advanced functionality in areas such as targeted drug delivery, wound healing, and tissue engineering; and (6) The nano-sized biopolymer-based materials and their nano-composites have found extensive applications in drug deliveries, tissue engineering, diagnostics and therapeutics.