But seriously, as far as I'm aware (and I try to stay current on this topic), there is no 'medicine' out there with "centuries of empirical evidence" that isn't already accepted. There are loads of compounds that claim to be effective, but when tested they are found to be no better than placebo.

Even if a compound is found to be effective, it isn't enough to make a good medicine. The active ingredient needs to be identified, extracted, and stabilised in a product that allows doctors to safely control the dose that a patient receives. Skipping all of that work and just trying to take an uncontrolled substance is dangerous - you can't tell if the active compound has broken down, or just isn't present in a particular sample, or conversely, is present in dangerous amounts. Furthermore, the naturally occurring compound may have other, undesirable compounds included with it.

Modern medicine aims to control for all of this, and yes, the complexity can be off-putting compared to the simplicity of "natural" solutions, but there are good reasons for that complexity existing.

What you want, and everyone wants, is fair, unbiased testing of any medicine, regardless of origin. Peer reviewed science and FDA approval tests are not perfect, but in the vast majority of cases they are better than "centuries of empirical evidence." The placebo effect is very real; if people are paying money, betting their lives, and putting potentially dangerous compounds into their bodies (whatever the origin), then we'd like better than that.

Also, I would add that alternative medicines tend to fail by not working at all, whereas (what we'll call) lab medicines tend to fail by having unforeseen, unexpected, longer-term side effects.