Horse meat from Poland tested positive for "Bute".   Bute is a banned medication because it's really toxic to humans.  ~Declan 

Polish horse meat tested positive for banned drug

AP /  April 2, 2013

As posted on Boston.com

PRAGUE (AP) — The Czech Republic veterinary authority says horse meat imported from Poland tested positive for phenylbutazone, a drug given to horses that can cause health problems in humans.

Horse meat from the animals treated with the drug is banned from being sold in the European Union.

Josef Duben, spokesman for the authority, said Tuesday the drug was detected in correctly labeled horse meat on sale in a store in the eastern city of Ostrava near the Polish border. Authorities so far are aware of about 300 kilograms (661 pounds) of the tainted meat delivered from Poland to the store.

Thousands of meat products are being tested for the drug, and for horse DNA, after horsemeat was found in food products labeled as beef or pork across Europe.