Source: The Great Interpretation of Dreams (Ibn Sirin)
Drinking human blood in a dream indicates gaining wealth and benefit from that person, or salvation from their evil if they are an enemy.
Source: Perfuming Humanity in the Expression of Dreams (Al-Nabulsi)
Drinking blood indicates unlawful money or sin.
Source: Signs in the Science of Expressions (Ibn Shaheen)
Drinking blood is interpreted as unlawful money or committing a sin.