It is common practice to flush expired medications down the toilet or a drain to prevent accidental ingestion. But when they enter the sewage system, wastewater treatment plants are not designed to remove pharmaceutical compounds. Regardless of the level of treatment, most conventional treatments are not effective in eliminating these man-made pollutants . When disposed at landfills or septic tanks, they can also seep through the soil or groundwater. The best thing to do is to return unwanted, leftover or expired medications to a nearby hospital or pharmacies where they can be properly disposed of. If this isn’t allowed in your area, contact your local hazardous waste facility to see if they have any recommendations. If you must dispose of them in the trash, keep them in their original containers. Modify the contents to discourage consumption: add water to pills, kitty litter or flour to liquids. Seal and double wrap in non-transparent bags. Discard in garbage, not recycling bins. This is still safer than the sewer.