Using Outdated Herbs

What might adverse side affects be, if any, from taking two black walnut hull supplements that were outdated by five years?

To my knowledge, this is not an area that has had a lot of research. However, from my limited study on the subject, plant degradation most often occurs from microbial, enzyme and oxidative involvement. As a result, plant constituents start to be broken down into other varied and numerous constituents at which point the medicinal or adverse effects would be unknown. It is doubtful that the old black walnut hulls would be dangerous to take at this point but at the same time, it would not provide the optimal medicinal healing that fresh walnut hulls could provide. My advise, add the old walnut hulls to the compost heap and purchase a fresh batch.