For example Ayurvedic medicine is very famous in India and people have been regularly using them for centuries for ailments ranging from tooth ache to fertility. The same is true in China and some other countries. However in the U.S., strict regulations hamper research which means that while there are herbal alternatives available, they cannot make any specific claim and they do not have the very coveted FDA approval. The dangers of herbal medicine are limited. It is good to know that most herbal medicines are safe. The worst they can do is not work at all and hence the condition stays the same. They cannot worsen a person's condition but and this is a very important but, herbal medicines need to be of extremely good quality in order to be completely safe. In other words, the main issue with herbal drugs is poor quality. While herbs cannot harm a person, they can do so if drugs are not made with good quality substances. When manufacturing herbal medicines both intrinsic and extrinsic features have to be evaluated for quality control. This kind of control...

This can definitely hurt a person's health and deteriorate his condition. But good research capabilities can make quality less of an issue. In Pakistan for example, Hamdard Inc. has very sophisticated research facilities and hence their herbal medicines are very popular. The same can be done in the U.S. If FDA makes things more hospital for advancement of herbal medicine.
Reference

WHO national survey on the use of herbal medicine: Retrieved online 14th June 2009 http://whqlibdoc.who.int/publications/2005/9241593237.pdf

American Botanical Council Calls for Expert Herb Advisory Panel. Herbal Science Group Clarifies Herbal Regulation Issues. American Botanical Council 18 December 2002 http://www.supplementquality.com/editorials/ABC_herbal_regulation.html

Summary Of Regulations in Various countries. http://courses.nres.uiuc.edu/hort180/InterRegHerb.pdf

American Botanical Council, 2002