Low ferritin may be caused by chronic bleeding, poor dietary habits, and long-term diarrhea. 1. Chronic bleeding: If the body loses too much blood or has chronic bleeding disorders, it may lead to low ferritin. For example, women who have excessive menstrual flow, or suffer from hemorrhoids, peptic ulcers and other diseases, may lead to gastrointestinal bleeding, causing low ferritin. 2. Bad dietary habits: Due to long-term lack of iron-rich foods in the diet, such as irrational diet, picky eating, partiality, etc., the body may appear low ferritin adverse conditions. 3. Prolonged diarrhea: If the patient has diarrhea for a long period of time, it will lead to malnutrition, which will cause poor iron intake, so low ferritin occurs. When low ferritin occurs, it is necessary to supplement iron in time, and it is recommended to eat more iron-rich foods, or take iron medicines such as ferrous sulfate and fumaric acid under the guidance of a doctor.