I suffer from psoriasis. Avoiding gluten made a significant difference in symptom reduction. I know that this isn't really "alternative", but many people do poke fun at people who avoid gluten.

Someone close to me died of cancer a few years ago. None of the many alternative treatments you can find online (some of them quite disgusting, but also the commonly mentioned ones... soursop, vitamin C, marijuana, etc) made any difference whatsoever. I assisted with some of them only because all medical avenues had already been exhausted (stage 4 pancreatic cancer) and she was grasping at straws and telling her there was no hope would have been cruel.

I'm not sure you'd call kava "alternative medicine" (most people use it as a recreational beverage rather than a medicine), but it's an anxiolytic drink that works wonderfully as a substitute for benzos and alcohol, without the addictive potential.