Spain arrested 14 people and seized more than three million doses of banned growth hormones in a crackdown on trafficking of performance-enhancing drugs in sports, officials said on Thursday.
It was one of the biggest hauls of its kind in Europe, justice officials in Valencia, eastern Spain, said.
Two of those arrested were held on remand in Malaga, southern Spain, while the rest were released but remain under investigation for a "public health offence".
It came after authorities carried out 26 searches last week, a judicial source told AFP, without disclosing the nationalities of those arrested.
Spanish police in September dismantled a network said to have been led by a doctor and a law-enforcement official who sold performance-enhancing substances in the north of Spain to both professional and amateur sportsmen.