The reason why bubble gum is pink is because the inventor only had pink colouring left. Ever since then, the colour of bubble gum has been predominantly pink

In 1928, Walter E. Diemer, an accountant for the Fleer Chewing Gum Company in Philadelphia, was experimenting with new gum recipes. One recipe was found to be less sticky than regular chewing gum, and stretched more easily. This gum became highly successful and was eventually named by the president of Fleer as Dubble Bubble. The original bubble gum was pink because that was the only dye Diemer had on hand at the time and it was his favorite colour.

To test his recipe, Diemer took samples of the new gum to a local store where it sold out in a single day. To help sell the new Dubble Bubble gum, Diemer taught salespeople how to blow bubbles so that they could teach potential customers. Dubble Bubble remained the only bubble gum on the market until Bazooka entered after World War II.

In modern chewing gum, if natural rubber such as chicle is used, it must pass several purity and cleanliness tests. However, most modern types of chewing gum use synthetic gum based materials. These materials allow for longer-lasting flavour, a better texture, and a reduction in tackiness.