Anemia is when the level of red blood cells in your body goes below normal. When you do not have enough red blood cells, different parts of your body are not getting enough oxygen. As a result, they cannot work the way they should and cause problems.

You can develop anemia if your body does not make enough red blood cells or destroys them. You can also develop anemia if you lose too much blood from your bloodstream. Anemia is a common side effect of cancer and many types of cancer treatment.