Except what we get with the ancient records regarding willow bark were just what we’d expect with folk medicine: anecdotal claims that it treats a wide range of ailments without any proposed mechanism of action.

It wasn’t until willow extract was actually made into a pharmaceutical that it became anywhere near useful. That willow tea you’re imagining ancient people drank didn’t actually exist and if it did, they were not getting enough salicylic acid from it to equal even a single aspirin.

https://theconversation.com/hippocrates-and-willow-bark-what-you-know-about-the-history-of-aspirin-is-probably-wrong-148087

In short, aspirin follows the above rule: alternative medicine was proven to work, and then became medicine. But the end result is far detached from how it was used thousands of years before it was actually shown to work.

Similarly many Chinese traditional medicinal techniques do work. Chinese medicine is undoubtedly "alternative medicine". You can cure aches and pains using medicinal herbs. They probably aren't as effective as scientifically synthesised compounds designed specifically for this purpose, but many of them actually work. Others are just placebo. The Chinese government regulates Chinese medicine in China and it is approved for use in many low-level medical applications. But if you have cancer, no herbs will save you and any claims to the contrary are just mere quackery.

Some Chinese medicinal techniques have made their way into "Western medicine", as it is called in China. The most famous traditional Chinese medicinal practice adapted this way is variolation, which was refined by science and become vaccination.