Lebanese customs seized five million banned captagon pills at Beirut port on Wednesday, an amphetamine shipment intended for Greece and Saudi Arabia, a customs official said.
Following a tip-off, officers had found the drugs hidden inside a tile-making machine, the official said, asking to remain anonymous as he was not allowed to speak to the press.
Three Lebanese citizens were detained over the affair, he said.
It was latest in a string of similar drug busts in Lebanon.
In 2015, a Saudi prince was detained as he tried to smuggle out two tonnes of captagon on a private plane from Beirut airport.
Captagon is an amphetamine manufactured in Lebanon and probably also in Syria and Iraq, mainly for consumption in Saudi Arabia, according to the French Observatory for Drugs and Drug Addiction (OFDT).
It has been one of the most commonly used drugs in the war in Syria, where fighters say it helps them stay awake for days.
Captagon is cheap and easy to manufacture, and experts say there have also been attempts to market it as a low-priced alternative to cocaine, including in the West.
In July last year, Italy seized a record 14-tonne haul of the drug -- or 84 million pills -- that had arrived from Syria.