To see if there is edema, we usually press on the patient’s inner ankle or the front of the shin bone to see if a crater will be made and if the patient will recover quickly after pressing. If a crater can be pressed and recovered quickly, it usually indicates the presence of edema. If the edema is not symmetrical, it is usually due to poor reflux, and the most common cause of poor reflux is poor venous reflux. In this case, the patient is usually asked to check the venous ultrasound of the lower extremities to see if there is thrombosis, varicose veins, etc. In addition, if the edema is bilateral and symmetrical, systemic causes are usually considered. The more common systemic causes include cardiogenic edema, hepatogenic edema, nephrogenic edema, endocrine-derived edema and idiopathic edema, which are mainly analyzed as follows: 1. Cardiogenic edema: first, we should see if there is cardiac insufficiency, and we can do electrocardiogram, cardiac ultrasound and, if necessary, plate test to see the condition of cardiac function. If there is cardiac insufficiency and there is edema, it usually means that the edema is of cardiogenic origin. 2. Hepatitis edema: see if there is cirrhosis, liver insufficiency, ascites, to help determine if it is hepatitis edema. 3. Nephrogenic edema: see if there is elevated protein, blood creatinine, urea nitrogen in the urine to determine if it is nephrogenic edema. 4. Endocrine edema: also check thyroid function to see if there is hypothyroidism, hyperthyroidism, to determine if it is endocrine edema. 5. Idiopathic edema: If a woman aged 20-50 has no clear cause for edema, often related to eating more salt or often in a bad mood, it may also be identified as an idiopathic edema. These are the general causes of fine legs in the morning and thick at night.