You’re doing really interesting work. A good friend of mine is a retired herbalist, after running a business for over thirty years and I’ve learned many things from her. Another old friend of mine is a qualified herbalist too, and it’s fascinating to talk to people who really know what they’re doing – that way you can discern between the genuine, beneficial use of herbal remedies and the old chestnuts to be discarded. As with all things, there’s a science to it and herbs/herbal remedies can be pretty powerful, so it’s always best to err on the side of caution if you ask me. If you get a good dictionary of herbalism, or you can find a reliable online source, they will always tell you what, how, why and when not to. It’s probably best to learn about each herb or plant at a time and build up your repertoire so to speak. A tip from a botanist would be to find out what the scientific (Latin) and the old vernacular names of these plants actually mean, especially the ones known to the ancient world, as that can often, albeit it not always, given you an insight into their properties.