1. I had told Fred never to borrow my car without permission again, but he did it anyway. That makes my blood boil.
2. The secretary could hardly believe what one of the office workers had said about her. She was angrier than she could ever remember being before. It made her blood boil.

Compare to: hopping mad; hot under the collar; boiling point. The expression suggests that when one is very angry, one’s blood gets so hot that it boils.