Does using DRANO or Liquid PLUMBER damage your pipes?
Not unless your pipes are already heavily damaged. Those kinds of products are for dissolving organic material like hair and food bits.
Drano works really good!!!!
I don't think using Drano or Liquid plumber damages your pipes, but it will depend on the pipes you use or they are already damaged. The links below have additional information about the products http://www.ehow.com/about_5315309_liquidplumr-vs-drano.html and http://en.wikipedia.org/wiki/Drano.
It can. It depends on type of pipe. You should call a professional because it will cost more if you damage the plumbing.