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Cotton in Medicine Bottles – What Is It For and Why Is It Disappearing?

You open a bottle of aspirin and pull out the cotton. But do you know that you should throw it away immediately? And that it isn't actually cotton?

Where Did the Cotton in Medicines Come From?

In the early 20th century, Bayer began placing a cotton ball in bottles of aspirin. The reason was purely practical: the tablets at the time were uncoated, brittle, and powdery. During transport, they would knock against the glass bottle walls and crumble into powder.

The cotton filled the empty space in the bottle and secured the tablets – it acted as a cushion that prevented the tablets from breaking during the journey from the factory to the pharmacy.

Popular Myth: Many people believe that the cotton is in the bottle to "absorb moisture" and keep the tablets dry. This is the opposite of the truth – cotton is hygroscopic (it absorbs moisture from the environment) and once the bottle is opened, it starts drawing moisture INSIDE. Therefore, the National Institutes of Health (NIH) recommend: remove the cotton immediately after the first opening.

It's Not Actually Cotton

Surprise: most of those "cotton balls" in medicine bottles are not real cotton. The pharmaceutical industry uses three types of material officially called pharmaceutical coil:

MaterialWhat It IsProperties
Cotton coilPurified, degreased, bleached cottonHygroscopic – absorbs moisture
Rayon coilBleached regenerated celluloseCan damage gelatin capsules through cross-linking
Polyester coilWhite, odorless syntheticDoes not absorb or release moisture – the safest option

Detailed requirements are defined by USP Chapter <670> (Auxiliary Packaging Components) – a standard of the United States Pharmacopeia.

Why Has Cotton Started to Disappear?

Two pivotal moments changed medicine packaging in America:

1984: Bayer Coats the Tablets

Bayer introduced the Toleraid® Micro-Coating, making aspirin tablets resistant to breaking. The mechanical reason for the existence of cotton – cushioning – ceased to exist.

1982: Tylenol and the Packaging Revolution

In Chicago, someone added potassium cyanide to Extra-Strength Tylenol capsules on store shelves. Seven people died. Johnson & Johnson recalled 31 million bottles. The case remains unsolved to this day.

The effect: the FDA mandated the use of tamper-evident packaging for all over-the-counter medications. Induction foil, shrink bands, and seals on caps emerged. Cotton was not part of this mandate, but the entire industry began to rethink packaging.

~1999: Bayer Officially Discontinues

The industry magazine Packaging World described this decision under the title “Bayer Kicks the Cotton Habit.” The company revealed that the decision to remove cotton had been maturing for four and a half years – such was the consumer attachment. People interpreted the absence of cotton as a sign of an opened package and refused to buy it.

Consumer Psychology

Manufacturers kept cotton for decades after it ceased to be necessary:

  • A bottle without cotton “seemed strange” – customers thought something was wrong
  • Cotton served as an informal indicator of tampering – absence of cotton = someone opened the bottle
  • It provided a sense of freshness and care – medications “seemed safer”

What Has Replaced Cotton?

  • Moisture absorbers (desiccant) – packets of silica gel or inserts in the cap. Unlike cotton, these should remain in the bottle
  • Blister packs – each tablet individually sealed in aluminum foil and plastic. They dominate in Europe; in the USA, only about 15% of tablets are packaged in blisters
  • Induction foil – a tight seal under the cap
  • Coated tablets – modern coatings eliminate brittleness

What About Poland and Europe?

Cotton in medicine bottles is a typically American phenomenon. In Europe, including Poland, the pharmaceutical industry has taken a different path – blisters have dominated since the 1970s.

The Polish company Polfa Kraków filed patents for blister packaging as early as the 1970s during the PRL. Blisters provide individual protection for each tablet: there is no need for cotton because the tablet has nothing to bump against. Additionally, blisters facilitate dosage control (you can see how many tablets are left) and are harder to counterfeit than bottles.

Fun Fact: The blister was invented in 1963 for... the contraceptive pill. The German company Schering AG needed a packaging solution that would help women adhere to the 21-day cycle of taking Anovlar – hence the numbered cavities arranged in a calendar format.

In the USA, blisters are still rare (about 15% of the market). Americans are accustomed to large bottles with hundreds of tablets – a typical scenario for medications like ibuprofen or vitamins, which are bought in “bulk” at Costco or Walmart.

Eight Things You Didn't Know About Cotton in Medicines

  1. You should throw it away immediately – NIH/MedlinePlus officially recommends removing the cotton after the first opening of the bottle because it attracts moisture
  2. It's usually not cotton – rayon and polyester are cheaper and more common
  3. Rayon can damage capsules – USP warns that rayon fibers react with gelatin during the cross-linking process
  4. Bayer took 4.5 years to decide to remove the cotton – such was the strength of tradition
  5. Bayer still uses cotton – in some enteric-coated tablets, cotton is still present
  6. Moisture absorbers are not the same as cotton – leave the silica gel packet in the bottle; throw away the cotton
  7. The Tylenol case was never solved – 7 victims, 31 million bottles recalled, but the perpetrator was never caught
  8. Poles never had this problem – blisters appeared in Poland early enough that cotton in medicines is almost unknown here

Official sources

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