Comparison of Silybum marianum (L.) Gaertn. with fluoxetine in the treatment of Obsessive-Compulsive Disorder

Prog Neuropsychopharmacol Biol Psychiatry. 2010 Mar 17;34(2):362-5. doi: 10.1016/j.pnpbp.2009.12.016. Epub 2009 Dec 24.


Obsessive-Compulsive Disorder (OCD) is a common neuropsychiatric condition. Although a variety of pharmaceutical agents is available for the treatment of OCD, psychiatrists often find that many patients cannot tolerate the side effects of these medications; do not respond properly to the treatment; or the medications lose their effectiveness after a period of treatment. Herbal medicine can be a solution to some of these problems. In fact many herbs with psychotropic effects exist which can have fewer side effects. They can provide an alternative treatment or be used to enhance the effectiveness of conventional anti-obsessive and compulsive symptoms. Silybum marianum (L.) Gaertn. is a well-known medicinal plant with a long history of usage in Iran. This plant is reported to be safe on humans. Our objective in this study was to compare the efficacy of the extract of S.marianum (L.) with fluoxetine in the treatment of OCD. The study was an 8-week pilot double-blind randomized trial. Thirty five adult outpatients who met the DSM-IV-TR criteria for OCD based on the structured clinical interview participated in the trial. The minimum score of Yale-Brown Scale for OCD was 21 for all patients. In this double-blind and randomized trial, patients were randomly assigned to receive either capsule of the extract (600 mg/day) or fluoxetine (30 mg/day) for 8 weeks. The results showed no significant difference between the extract and fluoxetine in the treatment of OCD. There was also no significant difference between the two groups in terms of observed side effects.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Antidepressive Agents, Second-Generation / therapeutic use*
  • Double-Blind Method
  • Female
  • Fluoxetine / therapeutic use*
  • Humans
  • Male
  • Obsessive-Compulsive Disorder / drug therapy*
  • Phytotherapy*
  • Plant Preparations / therapeutic use*
  • Psychiatric Status Rating Scales
  • Silybum marianum / chemistry*
  • Treatment Outcome
  • Young Adult


  • Antidepressive Agents, Second-Generation
  • Plant Preparations
  • Fluoxetine