Pharma guarantees exact amounts of the active compounds each single time. Herbal medicine can't, because 5 grams of this plant harvested at shadow is radically different than this other 5 grams of the same species but growing in a colder place, or in a sunnier place or in a short summer year, etc.
Therefore with herbal medicine there is always a risk of overdosing or receiving an useless (too low) dose. The importance of this fact when people deal with such evil things as Scopolamine shouldn't be dismissed.
To be fair most herbal medicinalists tout the decreased potency of an herbal drug as a major benefit. You're usually instructed to, for example, drink some amount of some tea for a month. It might be hard to predict the content of a dose but with most herbs even if you tried to overdose you'd probably just puke out all that plant matter rather than actually die
Every year there's between 10 and 60 total fatalities due to plant and mushroom poisoning annually in the United States. But more than 106,000 persons in the U.S. died from drug-involved overdose in 2021. Obviously many more people take pharmaceutical drugs than take herbal medicines, but I do think that even if you adjusted the numbers to account for that you'd still see a huge difference
The fact is humans have been eating plant matter for millions of years and even though secondary metabolites of plants can be unique, they still often have certain chemical properties that our digestive system can evolve to account for. For example oxalic acid (rhubarb, brown rice, almonds, etc) and saponins (beans, asparagus, spinach, etc) are two very lethal poisons that will kill your cat but that us omnivores have evolved to neutralize and most of us consume daily. In comparison, pharmaceutical drugs are specifically isolated and optimized for potency and it's simply much more difficult for our bodies to adapt to individual chemicals like this (especially if they have novel chemical properties not seen in other parts of nature)
That's true to a large extent with pharmacological drugs, since you have huge variability between people's weights, life style and diets (alcohol use for example). Usually the problem can be mitigated by starting with a safe low dose and adjusting until a benefit is seen in either case.
The profit motive of pharmacological companies is to have repeat customers. So no real incentive to cure.
You can't really dismiss this as a concern, as it's reflected in reality. Americans are some of the most drugged people in the world. The number of drugs Americans are now taking is growing exponentially. Yet this hasn't translated into life expectancy gains at all.
If anything, chances are you will be given the most drugs in the last year of your life. The risk of complications from taking so many drugs, will probably be working against benefit. As you get worse, the doctors will try to increase the dose. A feedback loop of sorts.
Hey, it's not like I'm against modern medicine. It's just it's a little more complicated, when game theory comes into play and individuals/companies have incentives that aren't always aligned with your best interest.
Lots of medicine is not just historically derived from plants but actually manufactured from them - extracting and purifying an active ingredient from plant mass often is cheaper than synthesizing it chemically, so lots of widely used products from 'big pharma' effectively are herb-based.
However, this 'extracting and purifying' step is one that must be done, you don't want to give the patient the whole 'cocktail' of active substances that happen to be in the herb along with the one thing that does have the desireable effect; so skipping that step and using the herb directly often is not appropriate; sure, it can work and have some beneficial effect as it was used historically, but that's something you stop doing once you have the practical ability to do it better by properly extracting the appropriate component.
