Horse meat containing the veterinary drug bute may have entered the French food chain. The meat has been traced to a Taunton slaughterhouse. It was exported from Taunton to France before the test results were known. The Foods Standards Agency had tested 206 horse carcasses and found bute in 8 of them.
Bute is short for phenylbutazone. It is used to treat some types of human arthritis in the UK (though even this is banned in the USA), and it is used in animals as an anti-inflammatory drug. There are minimal health effects from consuming small amounts of it. However, it is no longer approved for meat animals as it can occasionally cause severe side effects, such as suppression of white blood cell production and a type of anaemia in some people.
The test results suggest that a significant proportion of horse meat contains bute. It has recently been discovered that some UK supermarket products masquerading as beef actually contained up to 100% horse, much of it from Romania. Bute has not been found in Findus lasagne - the product at the centre of the scandal - but it's impossible to test every single meat product sold recently. In other words, not only have unwitting UK consumers been eating horse, but they may have been eating potentially harmful horse.