Iron deficiency in infants, young children or adolescents may lead to crying, growth retardation, etc. Iron deficiency in women may lead to iron-deficiency anemia, which may lead to symptoms such as pallor, coldness and fear of cold. Iron deficiency in infants, young children and adolescents may result in crying, growth retardation, depression, irritability, poor concentration, poor memory and comprehension, xenophagia, picky eating and partiality. Some patients will have decreased immunity and are prone to fever, upper respiratory tract infections, cough and diarrhea. When iron deficiency in women leads to iron-deficiency anemia, patients will have pale face, easy fatigue, dizziness, shortness of breath, spoon-nails, mouth ulcers, xerostomia, coldness and fear of cold, insomnia and sleeplessness, and other manifestations. In addition, women suffering from iron deficiency anemia may also have menstrual irregularities such as scanty or heavy menstruation, amenorrhea and dysmenorrhea. Patients with iron deficiency symptoms such as pallor and dizziness should consult a doctor in time to find out the cause and take appropriate measures under the doctor’s guidance. Patients should eat more iron-rich foods, such as duck blood and chicken liver.