Sometimes it seems to really upset people that I am a scientist and also support herbal medicine.* Sometimes that really bugs me, and so here's my rant about why that's bullshit:
Many drugs are derived from ancient herbal remedies. Scientists work to figure out what aspect of the plant is having an effect, and purify it to make a pill, or artificially produce something similar that has a stronger effect. And that's great. Aspirin is a hell of a lot more effective than chewing on willow bark. But the issue is that sometimes we lose useful components in that process. Or we over-concentrate a substance to the point that it starts having adverse side effects, where the original herbal product did not.
It occurred to me recently that there is an excellent analogy from my job working on medical devices. When we change a component of our system, the upper level scientists stand around talking about literature and past research, and how in theory, this change should have no effect whatsoever on anything other than the intended change. And yet, most of the time, it does have a side effect. Something happens that we totally don't understand and we have to dig into until we can figure out why it's doing what it's doing. (This is why we are in R&D, and we test these things before they go out the door.) Sometimes we never figure out why, and the project just gets scrapped. Such is science in industry.
Bring that analogy to pharmaceuticals. It's one thing to test changes in a simple machine. You can make the change, then use the machine normally (or better yet, strain it to work at its limits) and see if anything's off. The human body is a hell of a lot more complicated, and there's a lot more variation from person to person. There are far more chances to get something wrong that doesn't get caught in testing. This is why I usually avoid brand new drugs until they've been on the market for a while.
Additionally, pharmaceutical companies usually have profit at the top of their concerns. That's capitalism for you; if the company can't make a profit, they won't survive. As Violet recently noted, this means that sometimes pharma companies will make a drug which is not necessarily the best possible drug, but the one that allows them to make money. A drug that doesn't make them money is useless to them.