A public education campaign is underway to encourage proper disposal of expired or unwanted medications.
Water treatment plants can't neutralize drugs that are flushed down the drain. Scientists suspect that both over-the-counter drugs and prescription medications may be harming fish and other aquatic life.
In addition to the environmental concern, it's important to keep drugs away from pets and other people, said Julie Johnson of the Minnesota Pharmacists Association.
"What they're recommending people do is mix any icky material with the drugs -- sawdust, kitty litter, coffee grounds — that makes the medication less appealing, renders it unusable, do all this and put it in a plastic bag and put it in the trash."
In addition, Johnson recommends using the occasional take-back events organized by police departments or other authorities. Several organizations in Minnesota are teaming up to raise public awareness about how to dispose of medicines properly.