According to the comparison between Bei Le's herbal essential oil and Yi Yan's herbal essential oil, Yi Yan's herbal essential oil is not omnipotent, but inherits the navel therapy of traditional Chinese medicine to recuperate children's diseases and improve their physique. The side effects of Bei Le herbal essential oil mainly include photosensitivity of essential oil, contact dermatitis of essential oil and primary irritating contact dermatitis.

Dropping essential oil on navel can help stimulate acupoints. Traditional Chinese medicine believes that navel is the innate foundation of human body and can help replenish Yuanyang; Western medicine believes that dripping essential oil at navel position is helpful to regulate the body's immunity and improve the internal environment.