Septic tanks are not designed to breakdown any other products beside digested waste and toilet paper.

A product may say "flushable", but what that really means is that it won't get clogged when the toilet is flushed, not that it will break down in the tank.  In fact, most toilet papers shouldn't really be flushed.  A good test to see if the toilet paper you use can be broken down by the septic tank, is to put some water in a jar and some of the toilet paper you use, and shake it vigerously.  If it shreds and breaks down in the jar, it's just fine for your septic system.

Also most other products are highly absorbent and can cause blockages at the baffle and in the pipes. They also make it hard when the tank is pumped as they can potentially clog the hose.

DO NOT FLUSH WIPES OR PAPER TOWELS!