What is the best response to a patient who tells you that he feels much better after trying a "cure" that is practiced by his cultural group but that you know may have dangerous consequences?

WHY DO YOU THINK THAT HELPED YOU? I would not discourage or oppose the patients cultural beliefs. If they believe that the cure is helping than there is no harm in letting them maintain their positive outlook. I would look at approaching the situation by dealing with it in terms of having secondary or alternate options. By educating them on what ails them and encourage the treatment as a precautionary and alternative solution. As a plan B to ensure success. If I was to tell them that their notions were unrealistic than I would surely push them away.

They wanted to make slaves out of them.they wanted force them to move off their landthey wanted to make them grow crops for very little pay.they refused to speak native american languages