You know the signs of a backed up toilet: the bowl is overflowing and the rest of the family runs for cover.
Your natural inclination, understandably, is probably to get as far away as possible from the germs and gunk, and then call a plumber to schedule an (expensive) emergency visit.
Be brave: You can usually fix a backed up toilet yourself.
The first step to keep a bad situation from getting worse is to remove the top of the tank and flip the rubber stopper in the bottom of the tank back over the drain hole.
This will stop the flow of water into the bowl.Next, place the cup of your toilet plunger snugly over the bowl's drain opening and give it a few vigorous pumps.
The idea is to force the obstruction beyond a U-shaped section of toilet pipe, called the "trap", and into the straighter (and wider) drainpipe. The blockage should then flow away, and take with it any backed-up water.
If your efforts are to no avail, the problem may lie elsewhere in the drainage system. But before you wave the white flag, give it one more try, this time by coating the plunger with petroleum jelly before you begin your pumping action.
Now place the plunger cup snugly over the bowl's drain opening once more and repeat your pumping action.
If your second effort doesn't stop the rising tide, or the toilet keeps clogging, the problem may lie elsewhere in the drainage system.
Now that you've ruled out a simple clog, it's time to call in that emergency plumber. While you wait: