Rav Nahman of Breslov warned to stay away from doctors [Sichot HaRan. Conversations of the Rav Nahman]. That was at a time 200 years ago when medicine was still based on the four elements. However this advice is still highly relevant. THERE are procedures and medicines that have been around for 50 years and are well established and are okay. But less than that 50 year period  one ought to avoid.