There is no clear age limit for Yinhu Cold & Flu San, it can be used externally at any age in infants under the guidance of traditional Chinese medicine practitioners and within the scope of the indications. It should be noted that Yinhu Cold & Flu Essence is a topical medicine and is prohibited to be taken. Yinhu Cold and Flu Essence is a kind of Chinese patent medicine, which is composed of Jingwu, Artemisia annua and Ailanthus, etc. This product has the efficacy of pungent and cool to relieve the epidermis and clear away heat and toxins. It has therapeutic effect on wind-heat cold resulting in malignant cold (fear of cold), nasal congestion, cough and other conditions. Its adverse reactions are not clear at present. Contraindication is prohibited for pregnant women. Precautions, this drug is for external use, avoid internal use, allergy to this product is prohibited, allergy with caution. Children and other special groups need to be used under the guidance of professional physicians and parental supervision. From the instruction manual of this product, Yinhu cold powder does not have a clear description of the applicable age group of infants, infants under the guidance of a Chinese physician, and within the scope of the indications can be used externally. If there is any discomfort, it is necessary to improve the relevant examination by the Chinese doctor after identification to clarify the diagnosis, and need to standardize the treatment, so as to avoid delaying the condition.