I reckon it must've started out as a term used by seafarers as it is almost always used in relation to sea sickness - by people with caucasion complexions.

Went deep sea fishing off Perth last December. One guy was really feeling the swell - went truly green around the gills. First time I'd seen such a classic example - would've laughed but figured, but for the grace of god there go I.

PS Caught one lousy scorpion fish all day. NOT worth the A$100 for the trip. Did however see a whale, that sort of made up for it. Heaps of them off the coast these days.

stales