The agency said one of the victims lost about 20,000 euros (21,176). After a young woman secretly slipped Valium into him, another suffered two heart attacks so that his accomplices could rob his house.
Europol complained that the gang targeted older men who were separated from their families, mostly from the southern Italian region of Calabria.
Women usually start having sex with men, then ask for money, often for health problems or on the pretext of helping sick family members. If they did not agree, some people would be blackmailed.
Europol said the gang had managed to earn more than 1 million euros ($ 1.1 million) and smuggled money through investments in real estate, cars and gold.
Authorities in Italy, Germany, Romania and the Netherlands, backed by Europol, searched the gang on Thursday, searching 23 homes, arresting 13 suspects and seizing electronic equipment and documents.
