Patients often ask how to dispose of unused, unwanted, or expired meds. There are no specific government guidelines for disposal by the consumer. Incineration is best but often not readily available. Flushing meds down the sink or toilet is common, but sewage treatment plants weren't designed to remove drugs, and treated water is now showing traces of many drugs. While the concentration of individual drugs may be low, there is concern that the presence of multiple drugs with similar mechanisms of action could lead to harmful effects through cumulative, long-term exposure. Some household hazardous waste programs accept drugs, but can not accept controlled substances such as narcotics. Pharmacies usually can't take back meds due to strict federal and state regulations. Although it is not desirable, medications may be placed in durable opaque packaging that does not indicate the contents and put in trash destined for an engineered landfill as close to garbage pick up time as possible. This causes less pollution, but children or animals might find them, so sprinkling with an unpalatable substance such as cayenne pepper may deter consumption.