My wife and I probably go thru 2-3kg a month of cashews. Probably our favourite snack and the wife adds them to much of the stir-fries and salads. Never any ill effects (and according to the health propaganda - probably very beneficial). Never struck me as a very oily nut either - not like peanuts or brazil nuts for example. I'd vote on getting the liver checked too. Gall bladder will usually give off enough pain to let you know it isn't happy. Liver tends to be quietly falling off the perch.
