The purpose of this study is to evaluate the influence of none-lubricated dry tube on the incidence of Postoperative Sore Throat (POST) after general anesthesia with endotracheal intubation.

Inclusion Criteria:

• patients aged between 20-80 years who were scheduled for surgery under general anesthesia requiring orotracheal intubation

Exclusion Criteria:

• history of gastroesophageal reflux disease (GERD)
• congenital or acquired abnormalities of the upper airway such as tumor, polyp, trauma, abscess, inflammation, infection, or foreign bodies
• previous airway surgery; increased risk of aspiration
• coagulation disorders
• previous history of difficult intubation or conditions with expected difficult airway including Mallampati classification ≥ 3 or thyromental distance < 6.5 cm
• Using the other intubation devices beyond the direct laryngoscopy such as lighted stylet or fiberoptic bronchoscopy
• symptoms of sore throat or upper respiratory tract infection
• expected to place nasogastric tube during perioperative period
• requiring nasotracheal intubation