Remember that household cleaners like toilet bowl cleaner and bleach are chemicals—and that mixing chemicals can often have undesirable and dangerous consequences. Toilet bowl cleaner is an acid, and bleach is made with chlorine. If mixed, the resulting chemical reaction releases chlorine gas, which is a hazardous substance. Exposure to this gas can result in a number of different health risks.
1 - Irritation of Eyes, Nose, and Throat
Chlorine gas causes damage to membranes such as skin and eyes. When your face is exposed to such gases, it can cause irritation and even damage to the eyes, nose, and throat.
2 - Lung Complications
Chlorine is a gas in its natural state, so exposure to it means contact with your lungs. Breathing chlorine gas can cause breathing difficulties or fluid in the lungs. Especially at risk are those with respiratory illnesses such as asthma although chlorine gas is dangerous to everyone.
3 - Death
Chlorine gas is poisonous. It has been used as a weapon during wartime and breathing it in high enough concentration can kill you.