The couple are suspected of receiving the drugs by post from India, police in the northeastern Catalonia region said in a statement.
Officers arrested the two on February 24 in Premia de Mar, a coastal town north of Barcelona.
They are accused of trafficking illegal medicine and belonging to a criminal organisation.
"They were selling more than 150,000 pills a month," which they received in parcels from India, "a country with a tradition of manufacturing illegal medicines for Europe", the statement added.
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Police investigated after a post office reported finding a punctured parcel containing a large number of erectile dysfunction pills.
It was addressed to a mobile phone accessory shop that the couple are suspected of running as a front.
Police raided the shop and the couple's home. They intercepted 65 parcels addressed to countries across Europe and seized more than 400,000 pills total.
A judge identified the 53-year-old man as the suspected leader of the racket and remanded him in custody, the statement added.