A record number of fake online pharmacies were shut down in May as part of a global crackdown.
More than 100,000 online marketplaces offering illicit drugs were removed as part of Interpol’s Operation Pangea.
In the UK, fake medicines worth more than $13m (£9.17m) were seized as part of the efforts.
It marked the biggest week for the operation since 2008, as criminals cashed in on the demand for Covid-related products.
Interpol, short for the International Criminal Police Organization, is based in Lyon, France, and facilitates international co-operation between police forces and crime control.
Between 18 and 25 May, 277 arrests were made involving 92 countries. and more than $20m worth of pharmaceuticals were seized as part of Interpol’s efforts.
Fake or unauthorised Covid-19 testing kits made up more than half of the illegal medical devices seized worldwide.
UK authorities removed more than 3,100 advertising links for the illegal sale and supply of unlicensed medicines as part of the operation.
Some 43 UK-based websites were also closed down.
Interpol’s Secretary General, Jurgen Stock, said the sale of illicit medicines put the lives of “thousands” of victims at risk.
“The online sale of illicit medicines continues to pose a threat to public safety, which is why operations such as Pangea remain vital in combating this global health scourge,” he said.
“As the pandemic forced more people to move their lives online, criminals were quick to target these new customers.”
He added: “As crimes continue to evolve amidst the Covid-19 pandemic, the authorities must remain vigilant in dismantling criminal networks involved in the proliferation of illicit pharmaceutical products especially in online platforms.”
The global pharmaceutical industry is worth more than $1tn.
Vast supply chains stretch all the way from key manufacturers in places such as China and India, to packaging warehouses in Europe, South America or Asia, to distributors sending medicines to every country in the world.
Last year, a BBC News investigation found fake drugs for sale in Africa, with counterfeiters exploiting growing gaps in the market.