Plastic has become an integral part of our daily lives. This is because plastic has excellent characteristics as a material for various everyday items that surround us and is a valuable material in all industrial fields. In particular, polyvinyl chloride (PVC) is a chemically stable material that is flexible and durable and is used in various medical equipment, including infusion bags and infusion tubes, in medical settings. Phthalate esters are added to PVC products used in medical equipment as plasticizers. Diethylhexyl phthalate (DEHP), in particular, penetrates between the PVC molecules, giving the resin flexibility, and is often added to PVC, polyvinylidene chloride, cellulose esters, rubber, etc., at a rate of around 40%. DEHP is added to infusion tubes and bags at 30–40%. However, due to additives in injection solutions, DEHP can leach from PVC infusion tubes and bags. This chapter will introduce a series of studies on DEHP leaching from PVC medical devices, particularly PVC infusion tubes. Injectable drugs containing immunosuppressants such as Cyclosporin and Tacrolimus contain surfactants such as Tween80 and HCO60. However, the amount of DEHP eluted increased with the concentration of these surfactants, the contact time with PVC, and rising temperatures. In addition, the amount of DEHP eluted increased around the critical micelle concentration (CMC) of Tween80 and HCO60. On the other hand, it was found that the amount of DEHP eluted could be controlled by varying the type and amount of sugar added. PVC infusion tubes and bags containing plasticizers that replace DEHP are now being used, but they are not widely used because they are expensive. When developing new pharmaceuticals, it is probably necessary to continue research on the elution of plasticizers and the adsorption and sorption of pharmaceutical molecules.