Bleach is a highly potent agent used in cleaning, and while most people are smart enough to abide by the warning labels and avoid drinking it, sometimes people still wonder what would happen if they did.
Despite being over 92% water, the active ingredient in bleach, sodium hypochlorite, is highly corrosive to organic tissue. While it comes diluted from the store, it can still be powerful enough to cause burns and skin irritation. When you get bleach on your hand, you can just wipe it off since it doesn't stay there for very long. But if you swallowed bleach, it would remain in the stomach for a while, and here in lies the problem.
As it sat there, your stomach and esophagus would experience severe burns. Depending on how much you drank, there could even be a chance of death unless you sought medical attention immediately. Assuming you can make it to the hospital in time, the bleach can be removed, and your life can be spared, but you'd still be in a lot of pain in the meantime.
To deal with your now damaged stomach and esophagus, you may have to undergo two surgical procedures known as an esophagectomy and colon interposition. During these, the stomach and part of the esophagus are removed and replaced with your small intestine, so you will be able to digest food. Since you'd lack a stomach for the rest of your life, you couldn't swallow solid foods anymore. Instead, they'd have to be ground up or liquefied first to make it easier on your remaining digestive tract.
Then again, you could just avoid this hassle altogether; never, and we mean NEVER swallow bleach.