Study aim: Comparison the effect of Curcumin with placebo on reducing pain intensity in patients with mild to moderate idiopathic carpal tunnel syndrome, in terms of age, body mass index, duration of illness, in reducing paresthesia, efficacy on the electrodiagnostic parameters Design: Double-blind randomized clinical trial with control group and parallel Settings and conduct: In the university clinic (Tooba), electrodiagnistic study was performed for all patients selected before treatment and the Boston Questionnaire is filled for them. Patients are evaluated 8 weeks after treatment. All patients and the physician assessing are blind. Participants/Inclusion and exclusion criteria: Inclusion criteria: female patients aged 18-65 years old; sign and symptoms of carpal tunnel syndrome: at least two symptoms or one symptom and one sign including: electrodiagnostic evidence suggestive of mild to moderate idiopathic carpal tunnel syndrome. Exclusion criteria: positive history of the curcumin hypersensitivity; cervical radiculopathy or brachial plexopathy; TOS, rotator teres syndrome, ulnar neuropathy clinical polyneuropathy rheumatologic disorders such as: rheumatoid arthritis, systemic sclerosis, lupus, amyloidosis and so on; endocrine disorders: diabetes, hypothyroid, conditions that mimic carpal tunnel syndrome; pregnancy and lactation; serious cardiovascular disease and kidney disease; intravenous injection at wrist over the past 6 months; a positive history of a fracture of the wrist; use of corticosteroids or analgesic drugs. Intervention groups: The case group used topical curcumin and the control group used placebo Main outcome variables: Reduced pain, reduced paresthesia, improved electrodiagnostic changes