This is a very strong herb that has now been regulated. It has been abused as a weight loss herb and has since been taken off the shelves. It is now only available from qualified practitioners. Chinese medicine practitioners use this herb as a bronchodialator for asthma and severe common colds. It is actually used very little in my pharmacy.
Asthma is commonly treated with acupuncture. I have often used acupuncture to stimulate the immune system as well as cupping and supplementing with chinese herbal medicine as an effective treatment. People usually respond with less wheezing, better sleep, decreased stress as well as better control of their symptoms.