Objective: Kakkonto, a Japanese herbal medicine, is frequently used to treat the common cold not only with a physician's prescription, but also in self-medication situations. This study aimed to examine whether Kakkonto prevents the aggravation of cold symptoms if taken at an early stage of illness compared with a well-selected Western-style multiple cold medicine.
Methods: This study was a multicenter, active drug-controlled, randomized trial. Adults 18 to 65 years of age who felt a touch of cold symptoms and visited 15 outpatient healthcare facilities within 48 hours of symptoms onset were enrolled. The participants were randomly assigned to two groups: one treated with Kakkonto (Kakkonto Extract-A, 6 g/day) (n=209) and one treated with a Western-style multiple cold medicine (Pabron Gold-A, 3.6 g/day) (n=198) for at most four days. The primary outcome of this study was the aggravation of cold, nasal, throat or bronchial symptoms, scored as moderate or severe and lasting for at least two days within five days after entry into the study.
Results: Among the 410 enrollees, 340 (168 in the Kakkonto group and 172 in the Pabron group) were included in the analyses. The proportion of participants whose colds were aggravated was 22.6% in the Kakkonto group and 25.0% in the Pabron group (p=0.66). The overall severity of the cold symptoms was not significantly different between the groups. No harmful adverse events occurred in either group.
Conclusion: Kakkonto did not significantly prevent the progression of cold symptoms, even when prescribed at an early stage of the disease.