The raids targeted six locations in London and two in Yorkshire. From these locations the UK Medicines and Health products Regulatory Agency (MHRA) seized painkillers, sedatives and anabolic steroids, as well as treatments for depression and erectile dysfunction.
Packaging, computers and money were also seized. The raids led to the arrest of six people believed to be linked to a gang in Asia.
Pfizer, Eli Lilly and Sanofi-Aventis have been sent information relating to the raids. Laboratory testing of the products will now take place to assess their authenticity.