The blood in The Tragedy of Macbeth represents the guilt and murders of Macbeth and Lady Macbeth. When Lady Macbeth plans to kill King Duncan, she invokes the murderous spirits: “Make my blood thick. Block the access and passage to remorse, so that no scrupulous visitation of nature shakes my bad purpose, nor maintains the peace between the effect and it! Come to my woman's breasts, and take my milk for gall, you murderous ministers, wherever in your blind substances you await the evil of nature. Come, thick night, and wrap yourself in the darkest smoke of hell, lest my sharp knife see the wound it makes, nor the sky peep through the blanket of darkness to cry 'Stop, stop'!" (Act 1 , scene 5) Lady Macbeth asks them to help her commit murder without feeling guilty. She asks them to poison her blood and turn the milk from her breast into poisonous acid. She is trying to commit murder and wants the hell smoke hide her sharp knife so she won't see what she's doing and so heaven won't be able to stop her for what she's about to do. When Macbeth killed King Duncan, he said: “All great Neptune's ocean will wash away this blood/ Will it clean from my hands? No, this hand of mine will prefer / the countless seas incarnate, making the green one red.” (Act 2, scene 2) This means that Macbeth's guilt has grown and that not even all the water of the oceans could wash away his guilt Saying: “make the green one red”.”