Herbal remedies work because many of them are the basis for refined medications: Fox Glove (digitalis) is the base for Digoxin, a heart med; Nightshade (Bella Donna) is the base for Atropine, a med used for heart arrhythmia and to enhance surgery medications; Yew bark is used to make a chemotherapy drug; Willow bark is used to make aspirin; Oregon Grape root (valerian) is a mild antibiotic; Ephedra is the base for Ephedrine, which was further refined into pseudoephedrine, a powerful decongestant and base for methamphetamine.
I'm not saying anyone would give the above named plants to their animals or children, but we do have to keep in mind that just because something is an herbal remedy, it does not mean it is safe. We have to be careful with all remedies to be sure of dosage and safety. Most herbal remedies sold at health food stores are safe. However, the thing to keep in mind is they are not regulated for strength or efficacy by any agency.
My point, though, was that just because something is safe for humans…that does not mean it is safe for animals. I think it was well taken. People need to remember our pets are not little humans. While they are mammals, they have different nutritional requirements and different metabolic processes than we do. A faster or slower metabolism can greatly influence what a substance will do inside any particular body, theirs and ours.