Guest
Sounds like you have a venting problem, as waste travels down the pipe it has to push and pull air through a Vent Pipe usually running up to the roof, you may want to check and see if it is clear or you may have faulty plumbing due to a bad installation.
Either way you will want to have this fixed cause you can have a contamination of sewer gas if any of the Traps go dry (That is the purpose of the p trap to always contain water to hold back sewer gas) and eventually you may have a stoppage build up from waste not correclty being dicharged of improper flow.
