Comparative clinical trial of castor oil and diclofenac sodium in patients with osteoarthritis

Phytother Res. 2009 Oct;23(10):1469-73. doi: 10.1002/ptr.2804.


A randomized, double-blind, comparative clinical study was conducted to compare the safety and efficacy of castor oil with diclofenac sodium in patients with knee osteoarthritis. Subjects with symptoms of knee osteoarthritis were given a castor oil capsule 0.9 mL (n = 50) thrice daily for 4 weeks or a capsule of diclofenac sodium (n = 50), 50 mg thrice daily for 4 weeks. The subjects completed an overall evaluation of symptom relief at 2 weeks and 4 weeks of completed treatment. The subjects were evaluated by clinical, routine laboratory and radiographic investigations for improvement of disease conditions and also for adverse drug reaction. On completion of 4 weeks treatment it was observed that both drugs were significantly effective in the treatment of knee osteoarthritis (p < 0.001) and adverse drug reactions were high with diclofenac sodium, whereas with castor oil there were no adverse effects reported. The present study indicates that castor oil can be used as an effective therapy in primary knee osteoarthritis.

Publication types

  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Castor Oil / administration & dosage
  • Castor Oil / adverse effects
  • Castor Oil / therapeutic use*
  • Diclofenac / administration & dosage
  • Diclofenac / adverse effects
  • Diclofenac / therapeutic use*
  • Double-Blind Method
  • Drug Therapy, Combination
  • Female
  • Humans
  • Male
  • Middle Aged
  • Osteoarthritis, Knee / drug therapy*
  • Plant Extracts / administration & dosage
  • Plant Extracts / adverse effects
  • Plant Extracts / therapeutic use*
  • Ricinus / chemistry*


  • Plant Extracts
  • Diclofenac
  • Castor Oil