A chemical is a chemical no matter what the source. Arsenic is a good example of this. Natural products are still chemicals, some products sold in a store do not have the quality control we are use to finding in things that are bottled. One must be very careful when switching medications, some stay in your blood system for a couple weeks and can be extremely dangerous to mix. St. Johns Wort has had good results but only for mild cases of depression, and last but not least, please inform your doctor of what you are taking ( her/his approval is up to you) but, if you have an adverse reation, atleast she/he will know what you have injested and what to do to help you. Just my two cents worth, hope it's worth more than that thought.
Yours Truely Jo-Ann