Kidney stones 0.4 centimeters are not particularly serious. Because the diameter of the stone is only 0.4 centimeters and stays in the process of kidney, it usually does not cause abnormal symptoms and hydronephrosis under normal circumstances. However, usually when the stone is discharged, it may cause abdominal pain or nausea, pain, vomiting and other symptoms. However, this symptom is relieved after the stone is expelled. For smaller stones, you may choose to take medication for stone expulsion under your doctor’s supervision to help the stones pass out of your body smoothly. During this period, one should drink more water, and the amount of water consumption can be maintained at 2,000 to 3,000 milliliters per day. Drinking more water can help expel kidney stones. In the process of removing stones, according to the physical condition, do some jumping exercises appropriately, which will help to expel the stones. In addition, in daily diet, we should pay attention to eat less salt and sugar, eat more vegetables and fruits, and try to avoid smoking and alcoholism. We should eat less food with high oxalic acid content such as spinach, eat less soy products and don’t eat too much animal protein. If you are not feeling well, you should consult a doctor in time, and under the doctor’s professional guidance, choose the appropriate treatment according to your personal physical condition.