Authorities uncovered more than 513,000 medicines in the container in Genoa, north-east Italy, where non-EU cargo is often subjected to checks, the financial police said in a statement.
The cargo included daily medicines and those used by surgeons, thought to have been shipped from China.
There were also 1,720 bottles of alcohol hidden among the medicine, police said.
Authorities seized the cargo and the importer, now released on bail, is facing charges of illegally importing the goods and violating taxes.
The seizure comes just weeks after reports of a criminal network stealing medicines from hospitals in Italy, which were then distributed across Europe. The Camorra mafia reportedly coordinated the illicit trade with their criminal counterparts in eastern Europe.