People have used opiate drugs for some 3,500 years. For most of that time, opiates consisted of crude opium cultivated from the poppy plant. In the early 1800s, morphine and codeine, more refined isolates of opium, were developed. These drugs were initially used for pain and cough control. In 1898, the Bayer Corporation further refined codeine into the drug we know as heroin. The initial thought was that by changing the chemical structure of codeine, a more powerful cough suppressant could be formed. In the last half of the twentieth century, further compounds were synthesized from the basic chemical structure of opium, including methadone.