This may indeed be the case with some remedies and therapies, but it cannot be assumed in general, that any kind of natural remedy is so harmless, that taking the wrong medication has no effect. The basic idea, behind this setting, is also contradictory: on the one hand one trusts in the effectiveness of natural medicine, but assumes so, that it remains ineffective and harmless, if you take the wrong drug.
This can be easily illustrated using the example of homeopathy: if a remedy can produce positive effects, one can hardly assume so, that it doesn't work, when you take it, without being sick (or the wrong disease). This criticism from the side of conventional medicine should be taken seriously and not judged too lightly - just because the remedies may come "from nature". (which is not even necessarily the case with homeopathy) they are not harmless and you can select and use them yourself without any problems.
In addition to this criticism of the "apparent harmlessness" of natural medicine, one should not completely ignore the methodical criticism of medicine. Not every method, that a naturopath develops and rediscovers must be functional and effective (even if the basic views of natural medicine cannot be dismissed out of hand). In this branch of medicine, the methodology is far less strict than in classical medicine, and the users are willing to experiment in the hope, either a success or at least no damage. Therefore, there are certainly a number of black sheep in this area, which, unfortunately, require caution and avoidance. The same applies to medical wellness as to normal wellness, that not everything, what is touted, must also be effective and “worth the money”.; some methods are even not only overpriced and ineffective, but possibly dangerous.