The advent of truly effective therapy of syphilis with the introduction and widespread use of penicillin in the 1940s contributed to the great decline of syphilis over the following decades. The rise in the late 1980s and early 1990s coincided with widespread use of crack cocaine and exchange of sex for money and/or drugs. As syphilis rates declined in the U.S. in the late 1990s, the Centers for Disease Control proposed a plan to eliminate syphilis in the United States.