If you have old prescription pills or medicine, the old way of thinking was to flush them down the toilet. The U.S. Fish and Wildlife Service advises against it; a chemical cocktail of medicines has disrupted our natural ecosystem to dangerous levels. To properly throw away your medicine, pour it into a plastic bag and dilute it with water. Then mix in kitty litter or sawdust and seal the bag shut. Throw it away in your regular trash where it will be properly disposed.