Macbeth had many symbols, which were linked to the themes in the play. One of the symbols would be blood, and the theme to follow through with it is murder, and the dread associated with murder. A lot of the scenes in the play, involving killing, have blood stated. Blood is a significant symbol, when connected to the theme of killing, and is used as a foreshadowing device as well.
The first reference of blood is one of honor, and occurs when Duncan sees the injured sergeant and says, "What bloody man is that?"(Act 1 Sc ii, line 1). This is symbolic of the brave fighter who has been injured in a heroic battle for his country. In the next passage, in which the sergeant says, "Which smok'd with bloody execution"(Act 1 Sc ii, line 18), he is referring to Macbeth's braveness. After that, Shakespeare exploits blood as a symbol, takes place in Act 2, when Macbeth is preparing to kill Duncan. He imagines a dagger, a bloody dagger at that, pointing towards Duncan's room. Macbeth describes it "And on thy blade and dudgeon gouts of blood, which was not so before.It is the bloody business which now informs thus to mine eyes." (Act 2, Scene ii, 55-58). In this scene, the blood foreshadows, that Macbeth is about to kill Duncan. It also reflects on his state of mind, where he fears of killing Duncan, because his mind is playing tricks on him. Shakespeare most likely put this in as premonition of murder and death to come later in the play.
Another example of bloods use as a symbol was Act 2, Scene ii. The symbol of blood was now used to show deceit and betrayal. Lady Macbeth starts this off when she asks the spirits to "Make thick my blood." What she is saying by this is that she wants to make herself numb to all feelings and ruthless for the actions that she is about to commend. In Act 2, Scene ii, Lines 11-12, "I laid their daggers ready; He could not miss them". Notice how she said their daggers.