The campaign, which also features an online spot, is the result of a collaboration across the health and pharmaceutical industries.
It has been developed in direct response to findings that more than 330,000 men buy prescription-only drugs from unregulated sources, such as internet sites, every year.
Dr David Gilen, Pfizer’s medical director, said: "We are thrilled to be collaborating with the Medicines and Healthcare Regulatory Authority and leading UK patient organisations to tackle the industry-wide problem of counterfeit medicines head-on.
"This advertising campaign forms part of a wider public education campaign launched by Pfizer last year to ensure the public is aware of the health risks they are taking by buying and consuming counterfeit medicines, potentially without even a proper diagnosis from a qualified healthcare professional."
The cinema creative shows a man coughing up a dead rat, having consumed a pill bought from an illegal website. The ad aims to put across the message that taking fake medicines could potentially be fatal with many of them containing ingredients such as rat poison.
The ad will run in 600 cinemas nationally until 5 March.
Medicines and Healthcare Regulatory Authority
Warn of the dangers in using illegal medication