We all have them at some point in our lives: outdated or unwanted medications lurking in the back of our medicine cabinets.

They can range from antibiotics we didn't finish, to over-the-counter medications for a cold long run its course, to an unwanted prescription with side effects. We may feel guilty throwing them out, think we may use them again for the next infection, or we really don't know what to do with them. So they get pushed further and further to the back of the drawer or cabinet.

Tossing things in the trash is the most common way to get rid of items in our lives, including unwanted medications. But a 2002 study by the United States Geological Survey showed that chemicals from discarded medications were found in 80% of the streams in the United States. And those chemicals have leached from medications tossed into the trash. Many people take the time to toss the container into the recycle bin, but the pills go into the trash. And most plastic garbage bags do not survive the trip intact from home to garbage trucks to landfill without tearing. Exposed to the elements, the pills quickly degrade and dissolve, ending up in groundwater and the local streams.

One previously recommended way to dispose of unwanted pills was to flush them down the toilet or pour liquid medications down the drain. This was thought to be a safe way to keep them out of the reach of children. Instead this has been shown to have a huge impact on the environment as well. The EPA has determined that waste water treatment facilities are not set up to filter these types of chemicals from water, and many medications, particularly hormones from birth control pills, are ending up in our drinking water supply. Other chemicals identified in our water supply are Valium, nicotine, and steroids, to name just a few.

Aside from the environmental impact of drugs in the ground and drinking water, drug theft, combined with identity theft from the information on the prescription bottle, is on the rise. Controlled substances with high street value, like Oxycontin, can be retrieved from a dumpster by anyone looking for a quick fix or looking to sell drugs. Leave the pills in the original bottle, and they've not only got the the drugs but they've also got your name and possibly your address, if they're motivated enough to look you up in the phone book. Not really the people you want knowing where you live.

One previously advocated "safe" method of disposal to thwart this behavior, cited on many drug disposal sites, including government sites, recommended placing pills in multiple layers of plastic bags and mixing pills with something unpalatable such as used kitty litter or cayenne pepper. However, dogs and wild animals are attracted to used kitty litter, smelling it even if it's encased in plastic, and can easily ingest the medications with disastrous results. It also introduces the pills back into the ecosystem.

So what's the answer? Many pharmacies are starting to collect unused medications for proper disposal. Call your local pharmacy or talk to your pharmacist the next time you get your prescription filled. You can also call area hospital pharmacies to see if they offer disposal programs.

Many municipalities are also starting their own medication drop-off events. In 2007, Madison, Wisconsin, hosted a Med Drop and collected over 1,600 pounds of unwanted medications. That's close to a ton of medications that stayed out of landfills and the drinking water supply of Dane County. Contact your city or county government to see if they host such an event, and if they don't, suggest that they do.

You can also be proactive in how you use medications. Ask your health care provider for samples of new medications if you suspect untoward side effects, or ask for a short term prescription, or ask that your pharmacist only fill half for you. If you do find the medication is not working as expected, you're not only left with less unwanted medication to dispose of, you're also spending less money.

Finish all of an antibiotic prescription you were given for your illness. Many of us stop taking them as soon as we feel better. Not only are you left with unwanted medication, but this continued practice leaves us with antibiotic resistant bacteria. When all of the bacteria are not killed because the course of antibiotics isn't finished, the remaining bacteria that have been exposed to the antibiotics develop resistance to those antibiotics, making them more difficult to treat over time.

Avoid buying over-the-counter medications in bulk unless you really need large quantities of pills. Over-the-counter medications do have expiration dates and lose effectiveness over time. Seasonal cold medicine for children is an example where purchasing the smallest amount may make the most sense. It's unlikely you'll need cold medicine once the cold and flu season has passed, and a large bottle may go to waste. Also keeping track of what you have before purchasing more medication will prevent buying something you already have.

We can make a difference in keeping unwanted and expired medications out of the landfills and drinking water supplies. It just takes a little forethought and planning and making conscious decisions.