Asian Plantain (Plantago asiatica) has a long history of use in traditional Chinese medicine (TCM) and other Asian herbal systems for treating or preventing colds. In TCM, the seeds and leaves of Plantago asiatica are believed to possess "cooling" and "detoxifying" properties, and are often included in herbal formulas designed to clear heat, expel phlegm, and support respiratory health. Such formulas are sometimes used at the early onset of cold symptoms to prevent progression or to relieve cough, sore throat, or congestion.

However, scientific validation for the specific use of Asian Plantain in cold prevention is limited. Some laboratory studies indicate that extracts of Plantago asiatica exhibit anti-inflammatory, immunomodulatory, and mild antimicrobial properties, which could theoretically support its role in managing respiratory infections. Nonetheless, these findings are mostly preclinical, involving cell cultures or animal models, and do not directly demonstrate efficacy in preventing colds in humans.

In summary, while the use of Asian Plantain for colds is well-rooted in traditional practice, especially in East Asia, robust scientific evidence supporting its effectiveness for this purpose in humans is lacking. Its rating is therefore based primarily on tradition, with a modest evidence score due to limited but suggestive preclinical research.