This is a randomized, placebo-controlled, triple blinded clinical study to evaluate the effects of topical linseed oil on the treatment of mild and moderate carpal tunnel syndrome.100 patients with primary idiopathic CTS aged between 18-65, after taking signed informed consent, according to the electrodiagnosis classification criteria with clinical picture correlated with CTS, are included in this trial. The main exclusion criteria included: recurrent carpal tunnel syndrome; Positive history of trauma or fracture of wrist bones, surgical release of median nerve, direct injection into carpal tunnel of wrist; Evidence of cervical radiculopathy in EMG; Systemic disease including neuropathies (rule out by nerve conduction study of ulnar nerves), collagen vascular diseases such as SLE, scleroderma and RA; Endocrine disease such as hypothyroidism, DM, and other disease-inducing neuropathy; Situations such as renal failure, alcoholism or poor medical condition; History of recent and ongoing use of corticosteroids or analgesics that could not be discontinued. 100 cases with mild and moderate CTS will allocate to two arms by using blocked randomization. Wrist splint is prescribed for both arms. Linseed oil and paraffin will be given as encoded, innominate bottles with the same shape and color.Both of them are prescribed as 5 drops, morning and night-time doses for 4 weeks. Electrodiagnostic classificationat and Boston questionnaire score for CTS, at the beginning time and after 4 weeks of trial, will be evaluated, as the primary outcome measures, by a single researcher.