> Does "if it works for you" > also go for things like > aspirin, antihistamines, > antihypertensives, > antibiotics, etc?

A lot of the time, yes. For example, I have a bad physical reaction to aspirin -- it makes me vomit. I've tried several times over my life, and each time I had the same result. It does not work for me in the common use, plain medical sense of the phrase.