Pretty much every "alternative" medical procedure or product for the gullible has one serious side effect: the potential for abandoning medicine that actually and empirically has an effect superior to placebos.

Prominent example, to make it a bit more real: Steve Jobs had a cancer with an excellent prognosis on real medicine but chose to handle it with... fruit juice, I think. Steve Jobs is now dead.

Oncologists write bitter and angry testimonials about patients they weren't able to save because those patients turned away from effective medicine. It's even more infuriating when ignorant parents make these decisions for their children.