The effect of a herbal formulation on the incidence and severity of upper respiratory symptoms in healthy volunteers: an open-label, randomised controlled clinical trial.

Introduction: Many traditional preparations with varying combinations of herbs have been used for over 1500 years to treat upper respiratory ailments, and reduce their incidence and severity. Link Samahan® is a formulation containing the extract of 14 such medicinal plants.

Objectives: To test the efficacy of Link Samahan® in reducing the incidence and severity of upper respiratory symptoms in consenting healthy volunteers.

Setting: MAS Linea Aqua, a factory with over 3000 employees, having its own health care centre with a qualified matron and visiting medical officers.

Methods: 956 healthy volunteers took daily either one sachet of Link Samahan® in hot water (test group,n=465, mean age 29.5 ± 7.7 years, women 418) or only plain tea (control group n=491, mean age 29.7 ± 7.9, women 448), for 84 consecutive days, and recorded the incidence and severity of 15 upper respiratory symptoms daily in a purpose-designed form.

Results: At the end of 84 days, when compared to the control group, the average incidence of symptoms in the test group showed highly significant reductions at p<0.001 for 6 symptoms and at p<0.005 for 3 symptoms,and at p<0.05 for the remaining 6. Reduction of average incidence over time also was highly significant (p<0.001) for 2 symptoms and (p<0.005) for 7, and significant (p<0.05) for 4 symptoms, but only marginal for the balance 2. Severity was significantly reduced (p<0.05) for 7 symptoms, and reduced also for the other 8 according to descriptive analysis, though not significant at the 5% level.

Conclusions: The results indicate that Link Samahan® taken as one sachet daily significantly reduces average incidence, incidence over time, and severity of 15 upper respiratory symptoms in healthy adults.