Be they liquid, gel or powder form, most of the drain cleaners you’ll find on store shelves use strong chemicals, and they come in liquid, gel and powder forms. All chemical reactions involve moving electrons, and drain cleaners work by either taking or giving electrons to the clogging substance, generating heat in the process. There are three main types of drain cleaners: Caustic, Oxidizing, and Acid.

Because most of these products generate heat, they may soften the polyvinyl chloride, or PVC, pipes found in homes today. However, such damage is rare if you use the drain cleaner as directed — damage is more likely to occur when drain cleaner is used on older, metal pipes.

Aside from their effect on pipes, there are other disadvantages to chemical drain cleaners. They’re extremely toxic if swallowed, and they can burn eyes, skin and mucous membranes and eat through clothing. They can release noxious fumes, and if used improperly, they can cause explosions. These products can also harm septic systems by killing beneficial bacteria, and they can mar bathroom and kitchen fixtures.

If you use chemical drain cleaners, read the directions carefully and heed all the warnings. Use the product in a well-ventilated area, wear rubber gloves, and keep children and pets away from the drain. Never mix different drain cleaners, and don’t use a plunger in conjunction with drain cleaners.