Polymers and composites are widely used in medicine, ranging from tubings and blood bags used outside the body, to prosthetic implants used inside the body. Among them, ultra-high molecular weight polyethylene (UHMWPE) is used in orthopedic implants such as hip replacement to reduce friction, polyethylene terephthalate (PET) and expanded polytetrafluoroethylene (ePTFE) are used to construct blood vessels, polypropylene (PP) is used to fabricate sutures, and polyvinyl chloride (PVC) is used to manufacture blood bags, to name a few. Composites are also used in medicine. A good example is catheter. Catheter is a small diameter and flexible long tube that is inserted into human body to form a passage for delivery or transportation purpose. The tube is often multilayer because that the outer and inner layers serve different purposes. A reinforcement wire may be integrated as well. Polymers and composites are widely used in biomedical research as well. In any biomedical lab, metals, glass and plastics are the three major categories of materials used. Polystyrene (PS) is probably the most used polymer in any biological lab: cell culture plates, petri dishes, and various tubes. PP is the material of choice for pipette tips. Polyethylene (PE) and PTFE are used to make membrane filters. To be used in medicine or biomedical field, a material has to meet rigorous requirements, including the quality of the polymer itself, the limitation to additives, and the requirement for the processing environment. It is safe to say that without advanced polymers and polymer composites many of the modern medical and biomedical technologies are impossible.