Be discerning. Complementary stuff like yoga, biofeedback, acupuncture, and most homeopathy is often remarkably helpful but does not pretend to cure; it's labor-intensive and most of us respect these practitioners. Anyone who suggests laetrile is an "alternative" to effective cancer treatment is asking you to place your life in danger. Just be smart and recognize claims too good to be true aren't true.
Complicated. Complementary/alternative medicine (cam) in my mind has less "proof" and more "anecdote" behind it. However, it's generally less likely to harm you directly than allopathic medicine.