Nearly 2.8 million Germans over 60 are addicted to medicines such as pain-killers, according to the national centre for addiction.
In its annual report on addiction, the DHS said: "1.7 to 2.8 million women and men over the age of 60 have a problematic use of psychotropic drugs or pain-killers or can be described as addicted."
More than one in four residents of nursing homes over the age of 70 are addicted to psychotropic drugs, the DHS estimated.
The organisation also released research on alcohol consumption in Germany, showing it was "stable, but at a high level."
In 2008, the average German adult drank the equivalent of 9.9 litres (17.4 pints) of pure alcohol per year, the DHS said.