Selling drugs.
Doctors might not be crazy about the idea, but patients are walking into their offices asking for specific drugs.  They have heard about them on TV or read about them in magazines.
Braus
P
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D000329:Advertising; D006801:Humans; D008389:Marketing of Health Services; D004364:Pharmaceutical Preparations / Q000191:economics*; D014481:United States
D004364:Pharmaceutical Preparations