Chemicals and toilets normally do not mix very well, especially if you mix chemicals in the toilet. Household cleaners should not be used in a toilet unless they are specifically labelled for use in toilets. Use caution before using a chemical to unclog a toilet, since these chemicals can put you and others at risk.
Read the Label
Before you pour a chemical down the toilet's drain, read the label thoroughly. If the label does not state specifically that the chemical is safe for use in a toilet, do not pour it into the toilet's drain. Some chemicals will react adversely with toilet cleaners, such as any bleach mixing with ammonia, leading to dangerous fumes being created, or even explosions that can crack the toilet and potentially injure you.
Other Clog Formulas
Some chemical toilet clog solutions exist, but do not use any that are designed for use in a regular drain. Other chemical clog cleaners will not sink to the location of the clog, but instead will sit toward the top of the drain and create an obstacle to any tool you wish to use on the clog later. For example, Drano makes a solution for slow toilets. The company cautions, though, that the product should not be used on a completely clogged toilet. The Drano solution also contains microorganisms that eat away any human waste build-up in the toilet's drain.
Plunging and Snaking
Remember that any chemical you put down the toilet's drain limits your ability to plunge the toilet. Plunging will often splash water out of the toilet's bowl, meaning if caustic chemicals are in the water, you could be burnt by the chemicals and require medical attention. Snaking through chemicals also presents a challenge, since you will need to clean off the snake entirely before you can place it anywhere; otherwise, the chemicals could come in contact with your skin or other surfaces, such as the bathroom's flooring, that would be damaged by the chemicals.
Some toilet clogs will not come free unless you remove the toilet. Normally, removing a toilet does not present a challenge a homeowner cannot conquer, but with chemicals in the drain, you are taking a big risk. If you do call a plumber to your house to deal with the clog, the plumber may charge extra just because of the presence of hazardous chemicals.