Briefly, backtoading is the practice of drawing up drug into the syringe of an injection drug user (IDU) and then transferring a portion of the solution into a second syringe belonging to another IDU by removing the plunger of the second syringe. Earlier literature referred to a practice called'frontloading'which involves removing the needle (rather than the plunger) from the second syringe and then drawing back the plunger to allow the first person to squirt in solution. However, most IDUs in the USA use diabetic syringes which have needles that cannot be detached. Therefore the plunger of the syringe must be removed to receive drug, and 'backtoading' is more frequently practised. Although these two different terms add descriptive precision, functionally frontloadingand backloadingare similar. It isfurther noted that the terms 'frontloading' and 'backloading' were coined by social scientists, and that the terms to describe this practice are varied (e.g. divid, ing, splitting) (Smith et at., 1992).