Traditional Chinese Medicine (TCM) has evolved a lot over the years. A practice that has been passed down from generations to generations, it is now trusted by many people, especially the Chinese people. TCM can be practiced by anyone who is qualified. However, there are many practitioners out there who are willing to ignore their patients' safety for money. Eu Yan Sang, however, has maintained its reputation by providing its customers with the best that they can offer.
I might be wrong that they are overpriced, but that's just my opinion. You can get Chinese herbs from any neighbourhood TCM shops and they would offer you the same herbs for a much cheaper price. However, unlike Eu Yan Sang, they do not provide services such as telling you how much you should take and what foods you should avoid.
All in all, Eu Yan Sang, although in my opinion is a little overpriced, has good customer services and it strives to do good for the general population!