You can follow this general rule - please do not add anything to the clay itself whether it is for internal or external application. You may however take food supplements and/or homeopathic remedies internally while applying clay EXTERNALLY. But if you are planning to take clay internally with some other food supplement / remedy, wait at least an hour in between the taking of the clay internally before taking the food supplement internally. That way you make sure that clay will not absorb the nutrients or the active ingredients in your remedy or supplement.