Bronnchitis can be due to viral or bacterial causes. The only way to know for sure is to either obtain a culture or observe a response (or lack) to antibiotics. It is very admirable that you are taking herbal and vitamin supplements for good health, however in the setting of illness it is highly advisable to seek treatment from an allopathic or osteopathic medical practitioner. Vitamin C is generally a beneficial supplement, however many herbs can cause changes in liver function, blood & immune function, or have other undocumented or unstudied results.