It depends. It might mean that there are no studies that show efficacy or the lack thereof. A lack of evidence doesn't mean it doesn't work. It depends on what

It depends. It might mean that there are no studies that show efficacy or the lack thereof. A lack of evidence doesn't mean it doesn't work. It depends on what you mean by 'evidence.' Take one or two reports. A scientist would say, 'that's an anecdote.' A lawyer would day, 'I can send you to jail with those two reports.'