Anemia is a condition in which you lack enough healthy red blood cells to carry adequate oxygen to your body's tissues. Having anemia can make you feel tired and weak. There are many forms of anemia, each with its own cause. Anemia can be temporary or long-term, and it can range from mild to severe. Without these nutrients, the body produces large, abnormal red blood cells that can't function properly. An inherited form of anemia where red blood cells are shaped like sickles or crescent moons.
