After infection by Clostridium tetani, tetanus can be diagnosed if the patient has typical manifestations such as clenched teeth, bitter smile face and painful muscle contracture. After Clostridium tetani enters the human body through a break in the skin and mucous membrane, it multiplies in large quantities under suitable conditions (anaerobic) and can produce hemolysin and spasmodic toxin, and the toxin diffuses to the central nervous system through the local nerve cells, leading to increased muscular excitability of the skeletal muscles throughout the body, which is diagnosed as tetanus. Generally, the onset of the disease occurs 3~24 days after the injury, and the patient may contract the biting muscle and the muscle of the back of the neck due to the action of the tetanus toxin, and the typical symptoms of tetanus such as a bitter smile, clenched teeth, angular retractions, and convulsions may appear. The patient may die of asphyxiation due to gradual paralysis of the respiratory muscles. Current research believes that the shorter the incubation period, the higher the mortality rate. Therefore, tetanus immunoglobulin or tetanus antitoxin should be injected routinely after the injury to prevent tetanus. If the patient has already developed pre-symptoms such as drooling or has developed typical symptoms of tetanus, it is recommended to seek immediate medical treatment.