Before eating from an old jar of pickles you discovered at the back of the refrigerator, you should always check the expiry date. Expiration dates are printed on consumable items and medication for health reasons. They indicate the date by which the content of the container should be used by and it's important to adhere to it or else you may run the risk of getting sick. Sometimes they can be hard to find, as not all dates are printed in the same location, so make sure you check each surface carefully.
Hold the package or container under good lighting. Look for a different colored rectangle, a label like "Best Before:" or "Use By:" or a small set of numbers and letters printed on one of the surfaces. The expiry date will be in a different font to the rest of the print.
Look at the side of the lid, the base, or the shoulder for the expiry date of the contents in glass or plastic jars. Occasionally dates printed on plastic jars will smudge so if you can't find one, it may have been accidentally rubbed off.
Look at the corners on the top and the sides of cardboard boxes like cereal or granola bars. Individually wrapped cookies or chocolate bars may not have an expiry date printed on them if they come from a larger package. Refer to the original, larger container they came in.
Discard the product if you cannot find the expiry date. Eating expired food may give you food poisoning.