Diethylhexyl phthalate (Di-2-ethylhexyl phthalate, DEHP), the most frequently occurring plasticiser in medical equipment manufactured from polymers of vinyl chloride, forms about 40% w/w of tubes and containers used for storing blood and for haemodialysis. The plasticiser leaches out into liquids with lipid contents, although it is very sparingly soluble in purely aqueous solutions. On infusion of 2-3 1 of stored blood, up to 200 mg DEHP may be transferred to the patient, while much higher quantities may be given during dialysis, which is moreover often repeated frequently over long periods. The acute toxicity of DEHP is very low (greater than 20 g/kg as LD50 in rats), and the ester is rapidly metabolised to products which are excreted in the urine and bile; chronic toxicity from the levels of dosage obtaining is thus very improbable. Carcenogenicity has never been demonstrable in animals, while teratological effects are of a very low order. The uses of DEHP fall into two major categories: polymer uses (e.g. consumer products such as footwear, shower curtains and toys, medical devices and commercial/industrial uses) and non-polymer uses (e.g. dielectric fluids, paints, adhesives and inks). Non-polymer uses represent less than 5% of the total DEHP used in the USA. Approximately 45% of total consumption of DEHP in the USA is for plasticizing various industrial and commercial products. Industrial and commercial uses of DEHP include resilient flooring, wall covering, roofing, aluminium foil coating/laminating, paper coating, extrudable moulds and profiles, electronic component parts, and wire and cable coating and jacketing. Medical devices comprise approximately 25% of total manufacturing use of DEHP in the USA. Medical devices that contain DEHP include PVC sheet materials such as intravenous bags, and tubing used in a variety of medical applications.