Are you wondering whether you can take your toothpaste on a long flight? Can you bring toothpaste on a plane is one of the most common questions of first-time travelers. TSA 3-1-1 rule applies to every liquid or paste item you carry. Liquid, in any form, must be in the limit of 3.4 ounces for each passenger on the plane, this includes items like toothpaste, perfumes, water, shampoo, conditioner, mouthwash, and so forth. Anything exceeding this limit will bind you to pay extra charges.