So THAT’s What The Colour Square On Toothpaste Tubes Is For

Did you know that supermarkets often add a little-known “Julian date” to packs of fresh fruit and veg?

These usually tell suppliers and stores when the produce was packed and are different from consumer-facing “best before” and “use by” dates.

Some thought that a similar source of information might lie on the bottoms of our toothpaste packs, too.

In 2024, for instance, a viral podcast clip suggested that the little patch may reveal whether the ingredients in the tube are “natural” or “chemical” (though that distinction is impossible to make).

That misinformed claim has since been thoroughly debunked. But it leaves another question – what are the markers actually for, then?

According to dental health company Colgate, they’re used in the manufacturing process.

When factories produce packs of toothpaste, they fill the tubes’ contents at speeds as fast as 200 containers a minute. Machines fill the opened cylinders with exact gram amounts of the product.

Then, they need to be closed (usually by heat sealing) to prevent the toothpaste from leaking and to stop bacteria and air from entering the tube.

To do this efficiently, the machine that clamps the containers needs to be given a target.

Colgate explains that these tell “light sensors where the end of the tube is so that it can be cut and sealed properly”.

Again, these have nothing to do with the colour of your toothpaste tube (previous, disproven conspiracy theories suggested that green squares meant an “all-natural” product, while black supposedly revealed “pure chemical” options).

If you’re curious about the contents of your toothpaste, though, there’s a simpler option: look at the ingredients list on the pack.

The NHS does say we should keep an eye out for this section, but not to check the hue of the machine-friendly block.

Instead, the health service advises we check the packaging to find a product that contains at least 1,350 parts per million (ppm) fluoride.

This helps to fight decay and can keep your teeth healthier for longer.