That's Health. The shocking story behind the safety features we now take for granted
When we collect a prescription from our local pharmacy or buy a packet of painkillers from the supermarket, we rarely give much thought to the packaging.
Tablets are frequently sealed individually in blister packs, bottles have tamper-evident seals, and some medicines come in containers designed to prevent children from opening them.
But have you ever wondered why these precautions became so important?
Part of the answer lies in a horrifying series of unsolved murders in Chicago in 1982, when an unknown killer turned ordinary painkillers into deadly weapons.
The Chicago Tylenol Murders
In September 1982, seven people in the Chicago area died after taking Extra-Strength Tylenol capsules that had been deliberately contaminated with potassium cyanide.
Tylenol, a popular American painkiller containing acetaminophen (known in Britain as paracetamol), was manufactured by Johnson & Johnson's subsidiary McNeil Consumer Products.
The victims had simply taken what they believed to be safe, everyday medication.
Investigators discovered that someone had apparently interfered with bottles of Tylenol after they had left the manufacturer, replacing the contents of some capsules with cyanide before returning the contaminated products to shop shelves.
The resulting deaths shocked America and triggered an enormous investigation.
Johnson & Johnson responded by recalling approximately 31 million bottles of Tylenol capsules, an action that became a landmark example of corporate crisis management.
The murders also exposed a frightening weakness in medicine packaging: consumers had little reliable way of knowing whether somebody had interfered with the contents before purchase.
A Revolution in Medicine Safety
The Chicago murders helped transform the way medicines were packaged and sold.
Manufacturers introduced increasingly sophisticated tamper-evident packaging, including foil seals, shrink bands, sealed cartons and other protective measures.
In the United States, the Food and Drug Administration introduced new tamper-resistant packaging requirements for many over-the-counter medicines.
The aim was straightforward: make unauthorised interference more difficult and, crucially, make it easier for customers to recognise when packaging had been opened or damaged.
The tragedy also accelerated the move away from easily opened capsules towards alternative formulations and more secure packaging.
Why Blister Packs Matter
Blister packaging, in which individual tablets or capsules are enclosed in separate compartments, provides several important benefits.
- Tamper evidence: Damage to an individual compartment may reveal that somebody has interfered with a medicine.
- Protection: Sealed compartments can help protect medicines against moisture, dirt and contamination.
- Dose management: Individual compartments make it easier to see how many tablets remain.
- Identification: Printed foil and packaging can carry important product information.
- Reduced handling: Patients need only remove the tablet they intend to take, leaving the others protected.
However, there is an important historical distinction.
Blister packs were already being used before the Chicago murders. The tragedy did not invent blister packaging, but it helped drive a much wider reassessment of medicine security and the adoption of tamper-evident protection.
Not every blister pack is child-resistant, and blister packaging alone cannot guarantee that a medicine has not been tampered with.
What About Britain?
In Britain, blister packaging has become a familiar feature of everyday medicines, particularly tablets and capsules.
However, the widespread use of blister packs in the UK cannot be attributed solely to the Chicago murders.
Medicine stability, manufacturing improvements, dispensing practices and patient safety have all contributed.
Another important development came in 1998, when the UK introduced restrictions on the quantities of paracetamol and certain other painkillers that could be sold in individual transactions.
These measures were intended primarily to reduce deaths and serious harm from overdoses, rather than prevent deliberate product tampering.
Blister packaging can also make it less convenient to remove large numbers of tablets quickly, although it is not a foolproof safeguard against overdose.
The Safety Lessons We Should Never Forget
More than four decades after the Chicago murders, the lessons remain relevant.
Always check medicine packaging before use. If a seal appears broken, a blister compartment is damaged, or tablets look different from what you normally receive, ask a pharmacist for advice before taking them.
Medicines should also be stored securely, out of the sight and reach of children.
And remember that child-resistant packaging is not childproof.
The Chicago Tylenol murders remain one of the most disturbing cases of deliberate product tampering in modern history.
Yet they also prompted changes that helped make medicines safer for millions of people.
The next time you press a tablet through its foil backing, consider the extraordinary history behind something so ordinary.
What looks like a simple piece of packaging is part of a much larger story about public trust, consumer protection and patient safety.
That's Health – Helping you understand the everyday things that protect your health.
