Source: Tafsir al-Ahlam al-Kabir (Ibn Sirin)
Blood in a dream is unlawful money or a great sin. Whoever sees himself stained with blood is wallowing in unlawful money or sin. Whoever drinks human blood will gain wealth and benefit from that person, or be saved from his evil. Spilled blood indicates strife and bloodshed. Blood exiting the body without a wound indicates a loss of wealth proportional to it if he is rich, or health if he is poor.
Source: Ta'tir al-Anam fi Ta'bir al-Manam (Al-Nabulsi)
Blood in a dream indicates its owner's life, strength, and wealth. Whoever sees himself spitting blood will be afflicted with a calamity in his wealth or fall into a dispute. Whoever sees a river of blood will be afflicted with a great calamity in that place. Vomiting blood is repentance from a sin or returning a trust.
Source: Al-Isharat fi Ilm al-Ibarat (Ibn Shahin)
The vision of blood is interpreted in two ways: unlawful money or a false deed for which he sins. Whoever sees blood exiting his body, wealth will exit from him proportional to that blood. If it exits from the anus, it is unlawful money leaving him. Whoever sees himself fall into a well of blood will be afflicted with unlawful money or unlawful blood.