Ivermectin has been called a Covid "miracle" drug, championed by vaccine opponents, and recommended by health authorities in some countries. But the BBC can reveal there are serious errors in a number of key studies that the drug's promoters rely on.
For some years ivermectin has been a vital anti-parasitic medicine used to treat humans and animals.
But during the pandemic there has been a clamour from some proponents for using the drug for something else - to fight Covid and prevent deaths.
The health authorities in the US, UK and EU have found there is insufficient evidence for using the drug against Covid, but thousands of supporters, many of them anti-vaccine activists, have continued to vigorously campaign for its use.
Source: BBC News