The purpose of this study is to determine whether saffron is effective in the pain control after root canal therapy in vital teeth.

Among patients refer to endodontics department of Zahedan Faculty of Dentistry whom with moderate to severe pain in a single canal tooth will be selected and randomly divided in 2 groups of saffron and placebo. After root canal therapy each patient in each group will receive a box of 8 similar capsules. They will use 1 capsule exactly after treatment completion and then each 6 hours up to 48 hours. Patients will record their pain intensity in each time period according to Visual Analog Scale(VAS)and finally mean pain intensity will be compared between 2 groups.

Inclusion Criteria:

• patients who have at least one vital tooth with one root canal and moderate to severe pain

Exclusion Criteria:

1. teeth with periapical lesions

2. patients with history of:

   • allergy to saffron
   • diabetes mellitus
   • cardiovascular disorders
   • kidney and liver diseases
   • blood and hormonal disorders
   • electrolyte imbalance

3. women in pregnancy or breast feeding period and

4. use of analgesics or opioids during 4 hours before treatment