I was referring specifically to the medical part. an IV bag might have a half liter, but it's 500 "mil". ~28 grams in an ounce, which is unwieldy, even by american standards, and medicines are usually scant amounts of active ingredient, so milligrams is used.
Occasionally microgram is used, just as i have to occasionally measure things down to ~20 microns. I'd never use inches, there, and i'd never say "a kernel of corn weighs 1/250th of an ounce". This whole thread kinda caught me off guard. Normally i am making fun of the metric system, but something rubbed me the wrong way up-thread.
Ah. I was thinking of a comparable scale for liquids and fluids, as in, say, cooking. I can't decide if recipes that are obviously translated exactly from wierd-old American-and-British units but expressed in metric are more infuriating than ridicuolous or more ridicuolous than infuriating; probably six of one and half a dozen of the other: "Take 138 g butter and 267.5 ml milk..." No, for fuck's sake! Take 140 g butter and 250 ml milk! Or 150 and 300 -- i.e 3 dl. Sheesh...
Milligrams? Grams are already quite a bit smaller than an ounce. A millilitre of water weighs one gram.