The expiration time of local anesthesia is mainly related to factors such as the type, concentration, dosage and individual differences of local anesthetics. Generally, local anesthetics are divided into short-acting, medium-acting and long-acting. Short-acting local anesthetics have a duration of action of less than one hour, such as procaine, which usually lasts 30-45 minutes. Medium-acting local anesthetics have a duration of action of about 2-4 hours, such as lidocaine. Long-acting local anesthetics can act for 6-24 hours, such as ropivacaine, bupivacaine, if you add the appropriate amount of epinephrine, but also delay the absorption of local anesthetic, prolonging the duration of time, generally used in more vascular parts. Local anesthetic specific action time is also due to individual tolerance degree, there are some differences. In addition, local anesthesia has a certain risk, even if the chance of accidents is small, but still recommend that patients go to a regular hospital for treatment, so as to avoid adverse consequences.