Serum cholinesterase 2.5 is low compared with the normal value, which may indicate abnormal liver function, organophosphorus poisoning, renal insufficiency and other diseases, and there is a certain degree of danger, need to go to the hospital for further examination and treatment. Serum cholinesterase can hydrolyze acetylcholine after acetylcholine binds to receptors on the postsynaptic membrane and exerts a neuromuscular excitatory transmission effect. Serum cholinesterase is also an important indicator of protein synthesis by the liver. When cholinesterase is reduced in the blood, acetylcholine accumulates between the synaptic junctions and continues to act to keep the muscles excited, with serious consequences. The normal value of serum cholinesterase by enzyme rate assay is 4.3 to 10.5 U/L, and the normal value range varies with different assays and laboratory instruments. A serum cholinesterase of 2.5 below normal can be seen in severe hepatitis, active chronic hepatitis, hypoproteinemia (malnutrition, anemia, infections, myocardial infarction, etc.), organophosphorus toxicity, ulcerative colitis, renal insufficiency, and other diseases. When a patient detects a serum cholinesterase of 2.5, he or she should undergo regular examination and treatment under the guidance of a doctor to avoid aggravation of the condition.