Just do a google search. I don't think I can go as far as say I believe in making tinctures or planting crops based on full moon cycles, but I think there is something to humans/parasites, being effected by the gravitational pull of the moon, but it's not life changing in my opinion. If I make a cup of tea on a full moon, will it be stronger than 15 days earlier?
I just did a quick search, one reference stated that it could be that we are 60% water, and since we do know that the bodies of water on earth are effected, not by the moon itself, but that the stage of the moon indicates the gravitational pull the earth is experiencing at the time. That actually made sense to me.