I looked it up and out of about 10 sites I skimmed that applied to tablet form, not liquid amox, a couple came right out and said "do not freeze," but refrigeration was okay. I just went and stuck mine in the fridge. If it expires, it's still as potent for another year or two past that I surmise, and after that, it's maybe just slowly losing potency.I don't know. I have fishpen and aquamox. Unopened. I wish I knew best way to store and how long after it expires it would still effective.