In the face of increasingly sophisticated methods for avoiding detection, the company is hoping legal action can eradicate offenders where technology has failed.
Google has filed a lawsuit in a federal court against advertisers that have broken its rules, according to Michael Zwibelman, litigation counsel at Google.
"Despite our best efforts – from extensive verification procedures, to automated keyword blocking, to changing our ads policies – a small percentage of pharma ads from these rogue companies is still appearing on Google", he wrote in a company blog post.
Google plans to add offenders to the lawsuit as they are identified.
"Rogue pharmacies are bad for our users, for legitimate online pharmacies and for the entire e-commerce industry, so we are going to keep investing time and money to stop these kinds of harmful practices", wrote Zwibelman.
The move comes just days after eNom, the world's second-largest seller of website addresses, announced it would begin screening applicants to block bogus online pharmacies.
In response to growing pressure from authorities and internet governance group ICANN, eNom has teamed up with LegitScript, a company that vets internet pharmaceutical concerns to make sure they are licensed to do business in the US.
LegitScript will enable eNom to identify applicants who are operating online pharmacies in violation of state or federal law.
This story was first published by Computer Weekly