The design of an isolator and its use by an oncology satellite pharmacy for preparing cytotoxic drugs are described. The isolator (Iso Concept, Boulogne, France) is a totally enclosed ventilated biological-safety cabinet of class III polyvinyl chloride (PVC) with positive air pressure, a half-suit with a rotating seal, and attached neoprene gloves. There are three work-stations, one for the half-suit and two along one side of the isolator. The ventilation and air filtration system consists of one entry pipe with a full ventilation-filtration box fitted with one prefilter, one blower, one ball valve, one high-efficiency particulate air (HEPA) filter, one airtight nipple connected to an automatic sterilizer, alarms, and one exhaust pipe protected by a HEPA filter. The air lock consists of a rigid, transparent Plexiglas pass-through. The chamber is sterilized with heated compressed air mixed with 3.5% peracetic acid. Maintenance includes regular changing of gloves and HEPA filters; checking of the integrity of the PVC, half-suit, and gloves; and washing and decontamination procedures. Preparation of cytotoxics is planned in advance with prescription data and manufacturing sheets. In the half-suit, a pharmacy technician reads the label, supervises preparation of the sterile admixture, and writes a label. The operators on the side of the unit read the manufacturing sheet and prepare the dose identified by the label.(ABSTRACT TRUNCATED AT 250 WORDS)