How to unclog an overflowing toilet?

To unclog an overflowing toilet, first turn off the water supply to the toilet. Use a plunger to try and dislodge the blockage by creating a seal around the drain and pushing and pulling the plunger vigorously. If the plunger doesn't work, you can try using a toilet auger to break up the clog. If these methods don't work, you may need to call a plumber for assistance.