A randomized, double-blind, placebo-controlled exploratory study to evaluate the potential of pycnogenol for improving allergic rhinitis symptoms

Phytother Res. 2010 Aug;24(8):1115-9. doi: 10.1002/ptr.3232.


The potential of Pycnogenol for relieving allergic rhinitis (birch pollen) symptoms was explored in a double-blind, placebo-controlled trial. In 2008 19 subjects started treatment 3 weeks prior to the onset of birch pollen season in Ontario, Canada. While there was an improvement of eye and nasal symptoms with Pycnogenol, there was no significance versus placebo. It was postulated that Pycnogenol may require a lag-time between the start of therapy and the onset of action. Therefore 39 subjects were treated 5-8 weeks prior to the 2009 birch allergy season. The evaluation of subjects in 2009 showed much lower scores for eye (-35%) and nasal (-20.5%) symptoms with Pycnogenol compared with placebo. In succession of the allergy season birch specific IgE increased by 31.9% in the placebo group compared with only 19.4% in the Pycnogenol group. Detailed analysis suggested that symptom-relief was better the longer subjects were on Pycnogenol prior to the allergen exposure. The best results were found with subjects who took Pycnogenol 7-8 weeks ahead of the allergy season. With the limited number of 39 patients statistical predications were unattainable. In conclusion, Pycnogenol improved allergic rhinitis symptoms when supplementation was started at least 5 weeks before the onset of the allergy season.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Anti-Allergic Agents / administration & dosage
  • Anti-Allergic Agents / therapeutic use*
  • Betula / adverse effects
  • Double-Blind Method
  • Eye / physiopathology
  • Female
  • Flavonoids / administration & dosage
  • Flavonoids / therapeutic use*
  • Humans
  • Immunoglobulin E / blood
  • Male
  • Middle Aged
  • Nose / physiopathology
  • Ontario
  • Plant Extracts
  • Pollen / adverse effects
  • Rhinitis, Allergic, Seasonal / drug therapy*


  • Anti-Allergic Agents
  • Flavonoids
  • Plant Extracts
  • Immunoglobulin E
  • pycnogenols