6.4 Online databases.
Pubmed is a research database.
For research on herbs, filter for "Clinical Trial" and "Humans". It also makes sense to filter on "Free full text".
Those various filters cut down the results for Hypericum from 2324 to:
* "Clinical Trial": 214
* "Humans": 1224
* "Free full text": 385.
Combining all three leaves but 32 results.
The filters are needed because research in petri dishes or on rats, mice or pigs is largely irrelevant, and because abstracts lie.
Napralert is a commercial database on natural products.