It is normal for a blood clot to fall off on the third day of an extraction if the clot has undergone mechanization and granulation tissue has formed. If the extraction socket is empty and has a putrid odor, it may be abnormal and dry socket syndrome. 1. Physiological: the blood clot is gone may not be the blood clot shedding, but the blood clot has undergone mechanization. There is granulation tissue formation, which is a normal physiological phenomenon. 2. Pathological: If the blood clot in the extraction socket does fall out, the extraction socket is empty, and the bone wall inside is exposed in the mouth, and the bone wall is infected, forming dry socket. Then it is not normal. It is recommended to go to the stomatology department of the regular hospital as soon as possible for timely treatment. Specific advice to consult a professional doctor.