Low phosphorus 0.75mmol/L may cause symptoms such as bone fracture, mental irritability, loss of appetite, etc., and in severe cases, it may be life-threatening. The normal reference level for blood phosphorus is 0.97 to 1.61 mmol/L. Hypophosphatemia can be diagnosed when the level is lower than 0.8 mmol/L. Therefore, 0.75 mmol/L has already satisfied the diagnosis of hypophosphatemia. Mild hypophosphatemia may have no obvious symptoms, is relatively harmless, and most often improves with correction. Hypophosphorus may lead to neuropsychiatric symptoms, such as agitation, abnormal sensation, convulsions, coma, and even death; in addition, it may also cause skeletal and muscular symptoms, such as muscle weakness, muscle paralysis, as well as abnormal sensation, bone pain, rickets, and bone fracture. Severe low phosphorus can also lead to reduced diaphragm contractility, thus causing tissue hypoxia and acute respiratory failure. Damage to the heart muscle can lead to decreased blood flow, low blood pressure, and even congestive heart failure; in addition, it may also cause anorexia, nausea, vomiting, and so on. It is recommended to seek medical attention as soon as possible.