Compound 3D ferrous oral solution is mainly used for the treatment of iron deficiency anemia caused by chronic blood loss, pregnancy and childhood development. Common adverse reactions include gastrointestinal discomfort, such as nausea, vomiting, epigastric pain, constipation, etc. Black stools may appear after taking FERD. The dose should not be used for a long time, and should be used only after the diagnosis of iron deficiency anemia in hospital. Use with caution in patients with alcoholism, hepatitis, acute infection, intestinal tract infection, pancreatitis, etc.