Clogging. If clogging occurs, it is usually the result of an attempt to flush unsuitable items, or as feces size often increases with age or too much toilet paper. Clogging can occur spontaneously due to limescale fouling of the drain pipe, or by overloading the stool capacity of the toilet.
A clogged toilet is a hassle, but you can often fix the clog on your own. Make use of the rubber flapper in the toilet’s tank to prevent the water from overflowing. You may then be able to clear the clog right away with hot water. If this doesn’t work, a good plunger can eliminate most clogs, or you can use a toilet snake to manually move stubborn blockages and solid items. For deep clogs you can’t fix easily, consider calling a plumber to have them take care of the problem without damage to your toilet.