This time thieves broke in through a window of Totnes Hemp and stole up to £4,000 worth of herbal concoctions which are sold all over the world.
In October last year thieves stole around £12,000 worth of various seeds, including £2,000 worth of cannabis seeds, after causing £900 worth of damage breaking in through the front door.
Since then the company has installed sophisticated security equipment including alarms.
This time, the thieves got in through a second storey window some time between 3pm on Monday and 3.05am on Tuesday morning when an alarm at the building on the Babbage Road industrial estate was triggered.
Owner Chris Bovey said that the window had been thought to have been a low risk for burglars but someone had left some big containers below the window along with a ladder.
He said the company would now be reviewing its security all over again.
"We are alarmed and we believe they were disturbed," he said.
"They cleared a shelf but at the moment we are not sure exactly how much has gone because we have been asked not to touch anything before the fingerprint guys have been."
Totnes Hemp imports cannabis seeds mainly from Holland and legally sells them from its industrial estate premises where it has been based for the last three years.
The company has its own website advertising pot seeds along with 'legal highs', cacti, books, mushrooms and 'after party' products such as 'come down kits for clubbers and party animals'.
Mr Bovey explained much of the company business is mail order and its herbal highs are sold wholesale all over the world — including Russia, USA, Germany and Romania.