Blood flows through our veins and thus gives us vitality and vigour. That is why in the interpretation of dreams it is also associated with life energy and strength.
So if you have suffered a great loss of blood in your dream, this indicates that something in the waking world is robbing you of life energy or physical and mental strength. In terms of love and interpersonal relationships, the loss of blood can also mean that you are facing the loss of a loved one, or that you are trying to process this loss. Dreaming of bleeding to death can indicate an inevitably unpleasant situation in real life from which you try to find a way out without success.
Blood often occurs in connection with violence. If you bleed in a dream after a physical confrontation, the interpretation of the dream is that you should allow yourself more rest, as you seem to be stressed and agitated at the moment.
If, on the other hand, you do not lose blood in a dream, but instead receive blood donated through a blood transfusion, blood in this context is considered in the interpretation of dreams to be a dream symbol for a person or thing that gives you strength and will bring you success and happiness in the future or the long-awaited solution to a problem. If, as a dreaming person, you may even be supplying blood to someone else yourself or nursing their wounds, this may mean that you are empathetically caring for people close to you.