Ancient Wisdom is a catch all term for something that is invoked by pseudoscientists of all colours and stripes. It refers to practices that predate Christianity. It is often utilised by alternative medicine practitioners, especially when referencing practices from other cultures like Traditional Chinese Medicine. This adds a kudos to the practice because people have been practicing it for millennia, conveniently forgetting how shit life expectancy was prior to 1900 and the advancements made in actual medicine.
There’s a kind of logic in the idea that we wouldn’t have been doing the same things for such a long time if they didn’t work. This makes some sense but it assumes we started doing the practice for rational rather than irrational reasons. The older the practice the less likely it is to be founded in any kind of science or rationality. Though we have found actual medicine from some traditional practices, actual medicine will refine and improve things, making them more effective.
Appeals to ancient wisdom are often used by scam artists to give validity to what they are doing. Such as mediums and psychics that claim to have an ancient spirit guide.