Does Colgate contain any animal by-products? Is it kosher certified?
No, it does not contain animal by-products. No, it is not kosher certified. Source: Colgate.com
Toothpaste are Kosher because it is not pleasant tasting and not swallowed
The most kashrus sensitive ingredient often found in toothpaste is glycerin, which is often animal based, and usually makes up one-third of the product. Unquestionably, glycerin without a hechsher should be assumed non-kosher. Nevertheless, Rav Yackov Kaminetzky ztl ruled that kinds of toothpaste containing glycerin were permissible since the primary ingredient in toothpaste was calcium carbonate, which is inedible. Rav Yackov reasoned that the requirement of requiring 60 times the amount of heter in proportion to issur (bitul bishishim) did not apply to a non-food item. Since calcium carbonate constituted a majority of the paste, the glycerin would be nullified based on the principle of bitul berov. Source: Oukosher.org