The Mystery of the Colored Line on Your Toothpaste Tube

Have you ever noticed the small colored square or stripe printed on the end of a toothpaste tube? Red, blue, green, black—these tiny marks have inspired countless online theories claiming they reveal what's inside the toothpaste.

Some people believe the colors indicate whether a toothpaste is natural, chemical-free, or medicinal. While the idea sounds convincing, the truth is much simpler.

The Viral Myth

According to a popular internet rumor:

• Green = Natural ingredients
• Blue = Natural + medicinal ingredients
• Red = Natural + chemical ingredients
• Black = All chemical ingredients

Although this explanation has circulated widely online, it is not accurate.

What the Colored Mark Really Means

The colored square or stripe is known as an eye mark or registration mark. It is used during the manufacturing process, allowing packaging machines to detect where the tube should be cut, folded, or sealed.

These marks are intended for automated production equipment—not for consumers.

In other words, the color has absolutely no connection to the toothpaste's ingredients or quality.

If the colored marks don't tell you what's inside the tube, what should you actually look for when choosing a toothpaste? The answer is much more reliable.