Grape seed extract (GSE), used in traditional and herbal medicine as an antihistamine, does not relieve allergy symptoms, according to a study published in the Annals of Allergy, Asthma and Immunology.
Seeking to determine the clinical efficacy and safety of GSE in the treatment of seasonal allergic rhinitis, David I. Bernstein and colleagues from the University of Cincinnati administered either 100 milligrams of GSE (twice the recommended amount), or a placebo, to 54 allergy sufferers between the ages of 18 and 75.
The study began two to four weeks before the onset of ragweed pollination.
Study participants documented their symptoms for eight weeks via daily diaries, the Rhinoconjunctivitis Quality of Life Questionnaire (RQOL), global evaluations of treatment on the final visit and requirement for "rescue" antihistamines.
Slightly more than half of the members of both groups - 52 per cent of the experimental group and 54 per cent of those who received the inactive placebo - recorded good to moderately good responses to their treatments. Remaining subjects reported no response or worsening symptoms.
No significant differences were detected between GSE and placebo groups in symptom diary scores, rescue antihistamine, RQOL scores or peripheral eosinophil counts.
Researchers concluded that there was no trend supporting the efficacy of GSE in the treatment of seasonal allergic rhinitis.