In many cases it's not even “that medicine is poison, I use tumeric”, more often it's "I don't care, I'll keep drinking the sodas, eating the chips and not exercising". The folks into the tumeric, herbs etc. are also likely to be more into exercise and eating healthier so they end up with better outcomes not due to the tumeric (or whatever herbs), but because they have at least some interest in their health. The more difficult ones are like my BiL who told me recently that drinking full sugar sodas actually lower his blood sugar.