To save one's life one is allowed to tell a lie, drink/eat forbidden foods & so on. It appears to be that one can use any recourse whether allowed or not to save one's life.
Following the same premise, if one is suffering from a disease which is not curable from all the normal medical treatments that exist then can such a person go to someone who claim to treat successfully all such diseases through some untraditional approach which could be un-Islamic?
To quote a practical example, one of my friend is suffering from some sort of brain disorder which significantly curbs his thinking capability & could not be successfully traced & treated by allopaths, homeopaths, hakims etc. for the last 15 years. He has shown to almost all doctors and psychiatrics but in vain. He has come to know of an individual who diagnosed magic spell on him. The person offering treatment has a long history of treating such diseases. Is it allowed for my friend to ignore the methods of treatments and just take the prescribed treatments following the premise mentioned above? The friend is almost sure that he will be cured of his problem after this treatment based on his research as to the authenticity of that person. It should be noted that the person claims to have some powers through which he treats his patients. Is such a treatment Islamic? If not, then can my friend approach him for his treatment? If he should not approach because the treatment is un-Islamic then why the premise mentioned above will not apply here?
Islam has not held it forbidden (haram) to adopt any kind of treatment to cure the diseases. However, we are not always successful in curing a certain disease and people die. We can only adopt all universally acknowledged methods of treatment. We can get treated by any doctor or a psychologist or a quack. I do not think that getting treated by a magician would be considered sinful. But if the person who is applying charms etc wants you to utter polytheistic words or requires you to utter the Qur'anic words in distorted form then we must not do that. In this case we are losing our trust in God and are turning to His enemies.
This is not identical to the case where we are asked to denounce the religion on the gunpoint and we are sure that we will be killed if not yielded to the threats then we can act accordingly. This time we are facing our death being caused by another individual. This is not the Almighty himself testing us through disease (which is always part of the test and trial human are to pass through in this life on earth).
The case where we eat something forbidden (haram) to save ourselves also does not match with this one. For there we are only using something that is forbidden by the Almighty and allowed by Himself in case of compulsion. Here we are not taking something for a while but are deliberately sacrificing our faith for something we are not sure of. Cannot one have faith in God and leave the matter on Him and refuse to indulge in anything that is not allowed by the Almighty? That is why the Muslims do not even take their lives when they are sure of their death and are facing worst of the diseases like cancer etc. Please do write back if anything remains unclear.