evidence: Rumour has it that toothpaste color code means blue means the toothpaste composition is natural in combination with medicines, green means completely natural. [...] The toothpaste colour-coding system simply doesn’t exist. The colour on the bottom of your toothpaste means absolutely nothing about the ingredients, and you shouldn’t use it to help you decide on a toothpaste. [...] The colored squares on the tubes have no relationship with the content of the toothpaste. They are known as ‘color marks’ or ‘eye marks’, which are articles of the manufacturing process.