In this randomized double-blind trial, the effect of a herbal preparation on URTI symptoms was studied compared to placebo. Patients reported a significant decrease in URTI symptoms 20 minutes postadministration (P = .019). Analysis of a sub-population of patients with severe symptoms (46 participants) showed an even more significant difference between the treatment and placebo groups (P = .009).
As can be expected in upper respiratory tract infections, participants in both groups significantly improved after 3 days. No statistical difference was detected between the herbal and placebo groups after 3 days. These findings suggest that the studied herbal preparation possesses a local, rather than systemic, effect on the upper respiratory tract. Following 3 days of treatment, this beneficial effect was minimized, possibly due to natural improvement of patients' symptoms that typically characterize URTI ().
The trial was conducted in community family medicine clinics and, therefore, reflects URTI management in primary care rather than the more symptomatically severe population referred to ENT clinics and hospital departments.
This study has several limitations. The small sample size may limit the interpretation of the study results; hence, further research is warranted with a larger number of participants. In addition, although participants in the two groups had comparable characteristics, smoking in the control group was more prevalent and nearly significant (P = .052), thus possible influence of smoking on participants' taste and smell cannot be excluded. Another limitation is the use of only three points of clinical evaluation. Continuous measures of symptoms (e.g., patient's symptom diary) may contribute to learning about the clinical efficacy of the plant spray along the three days of evaluation. Another limitation is concerned with the theme of herbal safety. Although we did not observe any severe side effect symptoms, larger-scale studies are warranted in order to conclude the safety of the aromatic herbal formula. An additional limitation of our study relates to the challenging issue of blinding in herbal studies, especially when dealing with aromatic herbs. Although we did not assess participants' blindness, we did receive the participants' assessment regarding the smell and taste and their overall opinion regarding the spray's efficacy. Interestingly, participants receiving the aromatic spray reported a better smell compared to the placebo group, but fewer participants reported a good taste. In view of the fact that the aroma of aromatic herbs includes both smell and taste, we cannot conclude that blinding in our study was disrupted. Nevertheless, we recommend direct assessment of blinding in further clinical studies using aromatic herbs.
In order to clarify our findings, we reviewed the literature and found three randomized controlled studies that studied remedies containing aromatic herbs in a clinical setting of URTIs. Hubbert et al. studied the efficacy and tolerability of a spray with Salvia officinalis
(containing camphor) in the treatment of acute pharyngitis [18
]. The researchers reported that pain relief occurred within the first two hours after the first administration. In another double-blind randomized controlled herbal trial, Dirjomuljono et al. examined the effect of two herbs, Nigella sativa
and Phyllanthus niruri
, in patients with acute tonsillopharyngitis symptoms. In this study, the alleviation of swallowing pain and difficulty was noticed only after 5-6 hours, presumably due to a systemic effect (oral tablets versus spray application in other studies) [19
]. Design of herbal studies in the URTI setting needs to take into account the various herbal constituents and activities in order to choose the most appropriate route of administration. For example, Nigella sativa
, a well-known herbal remedy in Islamic medicine, possesses an antispasmodic effect and can increase mucociliary clearance; thus, a systemic rather than local activity may be expected [20
]. A third option for treating sore throat and other URTI symptoms is with a herbal tea preparation that may act both locally and systemically. Brinckmann et al. demonstrated significant relief of pain in patients with acute pharyngitis within 5 minutes after drinking Throat Coat
, a traditional demulcent herbal tea, compared with placebo [21
]. Other promising remedies are the traditional Japanese (Kampo medicine) formulas named Hochuekkito (TJ-41) and Juzentaihoto (TJ-48) that stimulate the mucosal immune system of upper respiratory tract [22
]. In our study, we designed application of aromatic oils in spray form rather than tea or tablets. We intended to gain the local benefit of these evaporating aromatic oils, which may attain better penetration of the tonsils' folders and other pharyngeal structures.
The rapid symptom improvement 20 minutes following application of the herbal spray may be explained by an anti-inflammatory and analgesic effect. Indeed, human and animal studies concluded that eucalyptus [14
] and mint oil [6
] possess these effects. The antitussive effect of menthol and camphor [7
] and the bronchodilating effect of carvacrol [10
] may also explain the rapid symptomatic relief observed in our study. However, this study cannot conclusively determine that the combination of the 5 herbs is indeed essential. Further clinical studies are warranted to determine the dosage of different herbs in the formula for relieving URTI symptoms and whether these herbs possess cumulative or synergistic effect.
The advantages of the aromatic preparation reported in our study may not be limited to patients' relief due to symptom improvement. Plant extracts are potential sources of antimicrobial and resistance-modifying agents and may be used to decrease antibiotic resistance [23
]. Moreover, utilization of complementary and alternative medicine (CAM) therapies, including herbal preparations, could reduce prescribing antibiotics in cases when there is no clinical indication, such as viral infections [24