A fallacy that claims that if something is natural, then it is good or right
This is a definition fallacy. Something is defined as good if it is natural and something is bad if it is unatural. The fallacy can be shown in two areas 1) there are natural things that cause harm (poisonous plants, excesses - too much heat or too much cold etc) and 2) the defintion of unatural i.e unatural things = man made things. But man is natural and so anythibng he or she creates is natural.