The typical clinical manifestations of diabetes mellitus are “three more and one less”, i.e., drinking more, eating more, urinating more, and losing weight. Due to individual differences, the degree of these four symptoms of diabetes can be mild or severe, or even absent, and the timing and order of symptoms can vary. Therefore, people who do not have “three more and one less” may also have diabetes. On the other hand, if you have unexplained physical weakness, loss of libido, impotence, menstrual disorders, back and leg pain, numbness and pain in the limbs, itchy skin, constipation, panic attacks, spontaneous sweating, incurable boils, sudden blurred vision, or delayed development in children, you should think that you may have diabetes.