Patients with iron deficiency anemia experiencing vomiting might have the following possible causes: Firstly, iron deficiency can lead to systemic hypoxia, including in the gastrointestinal tract, manifesting as reduced appetite and poor digestion. Severe cases may present with nausea and vomiting. This situation can be addressed by transfusing red blood cells and implementing aggressive iron supplementation to correct the anemia. Once the anemia is corrected, symptoms of nausea and vomiting should disappear. Concurrently, temporary use of anti-emetic medications such as metoclopramide can be considered to help control the vomiting. Secondly, some patients with iron deficiency anemia may have underlying gastric diseases that cause chronic bleeding, including gastric ulcers, gastric mucosal erosion, or even gastric cancer. These gastric diseases themselves can also lead to vomiting, necessitating further investigations like gastroscopy to establish a clear diagnosis and provide targeted treatment.