Do you mean you want to use a hemp rope to tie them up? Hemp ropes are normally fairly heavy, and would probably only be good on very large dogs. Plus it is very rough,, might cause skin irritation.
Some is as long as it is given in the correct dose. Here is a link to an article that may help you.
www.veterinarypracticenews.com/FAQ-What-You-Need-to-Know-Abo