The story
The figurative sense is a calque of an idiomatic expression from Chinese languages — 嘔血／呕血 (au² hyut³) in Cantonese and 吐血 (thò͘-hoeh) in Hokkien, for example.
Etymology from Wiktionary, CC BY-SA 4.0.
vomit blood
Today it means: Used other than figuratively or idiomatically: see vomit, blood. Full definition →