Transoral endoscopic thyroid surgery is a emerging surgical technique for thyroid surgery. This study to investigate the need for postoperative antibiotics in transoral endoscopic thyroid surgery.

To prevent possible infection from the oral cavity flora, most surgeons prescribe postoperative oral antibiotics more than 3 to 7 days after surgery. Currently, there's no clinical evidence that postoperative oral antibiotics is necessary or not in transoral endoscopic thyroid surgery. The investigator will conduct randomization after transoral thyroid surgery with two groups : postoperative oral antibiotics group versus no oral antibiotics group.

Inclusion Criteria:

• Patients who planned to Transoral endoscopic thyroidectomy
• Age between 20 to 70
• Voluntarily consenting to the study and study agreement
• No local invasion or distant metastasis
• Normal vocal cord function in laryngoscopic exam
• No significant abnormalities in preoperative laboratory tests

Exclusion Criteria:

• Take aspirin or antiplatelet drugs within 7 days before admission
• Uncontrolled hypertension, diabetes, chronic renal failure, or coagulation disease
• History of cardiovascular disease (angina pectoris, heart failure, myocardial infarction, history of coronary artery disease, stroke, transient ischemic attack)
• Substance abuse and alcohol abuse
• History of esophageal and airway diseases
• Patient was participated in other clinical trials within 30 days
• History of neck irradiation or surgery
• History of drug allergies
• Pregnant or lactating women