In the past, many people disposed of their unwanted medications by pouring them down the drain or flushing them down the toliet. But not all water treatment systems were able to clean the medicines out of the water,so they ended up in rivers,lakes and ground water. This can harm all animals-from fish to humans. Nowadys,most pharmacies and drug companies have programs that take care of this. If you send medicines you're not going to use back to them, they'll dispose of them safely