Herbs don't really have an expiry date but they do age and in the aging process the potency of the active ingredients decreases. When they were originally bought it would have been recommended that they were used within 6 months. After that time they degrade depending upon storage conditions. Obviously it’s best to keep then in a dry cool place. General advice for keeping herbal remedies, for example, Wormwood , is that they should be used within 2 years, so 2 years can be taken as the cut off date. Tinctures have a longer life of 3 to 5 years.