Roto-Rooter Pipe Shield Opinions

Hi, does anyone have good or bad experience with Roto-Rooter Pipe Shield? Supposedly you use it once a month as profilactic measure to keep pipes clear. Roto Rooter ad talks about “safe” and “natural” but why should I believe them?
In particular would it be safe for the aged plumbing of an old house?

By Jas |