An entrepreneur is selling "Da Vinci horse manure" just yards from the famous Rosslyn Chapel, which is about to feature in a Hollywood blockbuster.
Visitor numbers to the 14th-century chapel have trebled since it provided the setting for the dramatic ending of American author Dan Brown's best-selling 2004 novel, The Da Vinci Code.
They are expected to leap again next month following the release of the Hollywood film of the book.
But visitors have to walk past a clearly signposted wheelbarrow full of manure collected from a nearby field by a local horse owner. The bags sell at 50p a time.
Robin Crawford, owner of the Slatebarns Caravan Park, down the lane from the chapel, said the Da Vinci horse manure was his daughter-in-law Pam's idea.
"She has to go around collecting the manure from her horse Calypso anyway, so she thought she might as well make some money out of it for her kids," he said.
"Calling it Da Vinci manure was just a bit of laugh really - I don't know if she's actually read the book - and most people seem to be taking it that way.
"This is the right time of the year to be selling manure. This is when it should go on your garden."
Rosslyn Chapel - in the village of Roslin, six miles south of Edinburgh - has been a tourist attraction for centuries because of its intricate exterior, delicate internal carvings and links to the medieval Knights Templar and the Freemason movement.
Brown used the legends of Rosslyn - reputed to be the last resting place of the mythical Holy Grail - in the plot of his novel, which has sold more than 40 million copies worldwide.
But Crawford's family are not the only ones cashing in. Ye Olde Original Roslin Inn, on the village's Main Street, has just opened a Holy Grail restaurant.