The best natural way of reducing platelets may be as simple as doing nothing depending on what the reason for the high platelets is! Platelets in the body will rise in response to any sort of acute inflammation. So if for example you've just had a cold, it's very possible the platelets will be up. This will just go away spontaneously. If, though, you have high platelets because of overproduction by the bone marrow in conditions like essential thrombocytosis or accompanying a disease like polycythemia rubra vera, well, then there is no "natural" way to reduce this. You need to go on medications. (Well, one of the medications is aspirin which I guess is "natural" because it occurs in nature!