To bleed (physically); also used figuratively to mean suffering losses or making sacrifices (e.g., a company incurring heavy losses).
転んで膝をすりむき、血を流した。
He fell, scraped his knee, and bled.
その戦いでは多くの人が血を流した。
Many people shed blood in that battle.
新規事業で会社は初期に血を流すことが多いが、長期的には利益を見込んでいる。
A company often suffers losses early on in a new business, but expects profits in the long run.