In all due actuality, herbs don't spoil; but for the sake of technicality, the herbs/formulas in capsule form will remain good for at least 3 years from the date of purchase and the liquid extracts will remain good for at least 6 months from the date of purchase. Capsule formulas do not require refrigeration. However, liquid extracts will last longer if refrigerated. As long as you keep the herbs/formulas in a dark place and away from direct sunlight they'll last a good while.