In the present study we want to investigate the analgesic effects of vitamin C in the patients who undergo UPPP and tonsillectomy. Objectives: 1- To determine and compare the mean pain scores during the first 24 hours after the surgery in both groups. 2- To determine and compare the mean of the systolic, diastolic and arterial blood pressure and the mean heart rate during and after the surgery in both groups. 3- To determine and compare the time interval between the completion of the surgery and the first request for analgesic in both groups . Design: A Phase I or II, Single-Center, Randomized, Double-Blinded, Placebo-Controlled, clinical trial. Setting and conduction: Frothy patients who undergo uvulo-palato-pharyngoplasty and tonsillectomy are randomly divided into two groups by anesthesiologist. The patients are not aware of their groups. For all patients anesthesia induction and maintenance are similar. During the surgery, group C receives vitamin C and group P receives normal saline by anesthesiologist. An anesthesia resident, unaware of the patient’s group, fills out the questionnaires. Finally we will analyze the data with a statistical software. Participants: Patients with age of 25-50 years old, ASA (American Society of Anesthesia) physical status I or II ,who are going to have a UPPP and tonsillectomy, are included .Patients with mental retardation, epilepsy, BMI>35 kg/m2, history of chronic pain, liver or renal disease, drug allergy and drug abuse are excluded from the study. Intervention: During the first 30 minutes after the beginning of the surgery, group C receives infusion of 3 gr vitamin C in 500 ml Ringer and group P receives 5 ml normal saline in 500 ml Ringer. Main outcome measures: 1- Post operative pain 2- Heart rate 3- Systolic, diastolic and mean arterial blood pressure 4- Time of the first analgesic request