Most of a carton is required by regulation rather than chosen by a marketing department, which makes it unusually information-dense. A few minutes learning to read one is worth having.

The Batch Number Is the Thread

Every enquiry, every recall and every stability record is filed against the batch number. It is the single piece of text on the pack that lets a manufacturer find out exactly what happened to that specific medicine.

Expiry Is a Guarantee, Not a Cliff

The expiry date states the point up to which the manufacturer guarantees the stated potency and quality, stored as directed. It is not a prediction that anything dramatic happens the following morning — it is the end of what stability data supports.

The Storage Line Is a Condition of Both

"Store below 25°C, protected from light" is not advice. The expiry date is only valid under those conditions, and a pack left in a hot car has spent some of its shelf life in a way the date cannot show.

Conclusion

Batch number, expiry and storage line work together: one identifies the medicine, one bounds its life, and one states the conditions the bound was calculated for.