Can you give examples?

I think that for most autoimmune disorders the "modern medical" approach is to ameliorate the symptoms and that's about it.

CVD, the main killer in the developed world, is rather poorly understood. Oh, sure, we know the details of how the atherosclerotic process works, we just don't quite know what drives it. Or take a look at the metabolic syndrome -- even the name (a syndrome is a collection of symptoms, more or less) gives it away. Can we treat it other than by prescribing a bunch of statins and saying "eat less"? Can we cure diabetes, a VERY widespread ailment?

And that's even for diagnosable diseases. It's hard to find statistics, but it seems that it's not uncommon for people to be... suboptimal and the medicine just doesn't know what's happening inside them.