Toy Medical Carrycase £6 @ Amazon
I don't know what it is about playing at being medics that fascinates kids but there certainly seems to be something.
I am rather ashamed to say that this medical carry case is possibly better equipped than my household first-aid kit - it has absolutely everything in it to ensure that your little physician will be able to diagnose and cure every possible ill and ailment.
There is a stethoscope, a blood pressure monitor with working pump and meter, syringe with moving plunger, reflex hammer - beware your knees is all I can say, one of those instruments for looking inside ears with (an otoscope if you want to get really technical), a thermometer with moving part to display different temperatures, eye drop bottle, pill bottle with screw off lid, mirror for viewing throats and tonsils, tongue depressor and name badge with space for writing the name of your little MD.
I also think that kits like this whilst actively encourage role-play can also teach responsibility when it comes to dealing with proper medical equipment and supplies.
Thanks to Plum over at HUKD!