A 39-year-old Musselburgh man, and two Haddington residents, a 43-year-old man and a 35-year-old woman, will appear at Haddington Sheriff Court at a later date facing drugs charges.
The raid was part of Operation Erase, which has already seen 34 alleged drug dealers arrested and drugs valued at more than 330,000 seized in a targeted swoop on serious and organised crime in East Lothian.
Police today announced an expansion of the operation in the coming weeks to Midlothian.
Chief superintendent Mark Williams, divisional commander, said the recent arrests highlighted the police's commitment to ridding communities of the drugs trade. He urged the public to assist police investigations by providing details about drug activity in their area.
"We are determined to make local communities safer, and to improve the quality of life for the ordinary law-abiding people of East and Midlothian," he said.
Anyone who wishes to report drug-related criminal activity can contact 0131-311 3131 or 0800 555 111.