Willow bark is definitely the most common herbal medicine in any fiction book. No doubt that is because the very common real drug aspirin is directly related to it, so we all feel comfortable prescribing it.
Which of course means I need to try it. It is really quite simple. Strip the inner bark from willow twigs, ideally in the spring. Dry it out and slice it up.
The tea, steeped for quite a while (half an hour) in boiling water, yielded a surprisingly strong color with only a teaspoon or so of willow bark.
I drank some and survived. That’s all I really have to report. It didn’t taste particularly good, but nor was it particularly bad.