If you use them as directed, chemical drain cleaners may help to clear a partially clogged drain. 

But because they’re so powerful, we suggest using them as a last resort. 

So, yes, chemical drain cleaners can cause damage to your pipes, especially when:

• You have older, weak metal pipes
• You use them incorrectly with plastic pipes
• You use it on a completely blocked drain

You see, because they produce heat, chemical drain cleaners can warp or damage softer pipes like plastic and older metal piping.