Every now and then, you may come across a social media-circulated picture that claims the colored squares at the end of toothpaste tubes can tell you whether the product is natural or "chemical."
Green - all natural
Blue - natural + medicine
Red - natural + chemical
Black - all chemical
So, is it real or just a myth? It's actually fake! The rectangular color codes, known as "eye marks" or "color marks", are there to help manufacturing machines identify where the packaging material needs to cut or folded to create the tube. It has nothing to do with the contents of the toothpaste, which could be easily identified by reading the ingredients anyways.