It is also based on anecdotes and theories. But it is a huge and rapid growing industry. With the loosely weaved regulations and information on CT, patients have to educate themselves. This is crucial to avoid spending substantial money on ineffective therapies. As a strong proponent of CT, I am uncomfortable with the overuse of this word.
Petroleum is natural product from the earth.
Do not take herbal medicines without consultation with a certified herbalist. There could be interaction with other medications you are on. When you purchase herbal medicine make sure it has the standardised compounds listed on the label. There is also no guarantee that what is stated on a label equals the contents. So to a large extent it is word of mouth as to which brand has more quality assurance and effective ingredients.