Ukrainian prosecutors say they are preparing charges against the head of a Crimean winery for allegedly opening a 240-year-old bottle for Vladimir Putin and Silvio Berlusconi.
The Russian president and former Italian premier spent last weekend in Crimea touring ancient ruins.
Prosecutors say they drank at Crimea's renowned Massandra winery.
Massandra was Ukrainian government property before Russia's annexation of Crimea in March 2014.
Any charges could not currently be pursued in Crimea, where Russia has full control.
Russian media cited by Radio Free Europe reported that Berlusconi asked if he could sample the wine during a tour of Massandra.
A witness said Massandra's new pro-Russian director Yanina Pavlenko in response uncorked a precious bottle of 1775 Jeres de la Frontera for her prestigious guests.
Russian television last week showed Mr Berlusconi carefully surveying dust-covered bottles of wine while the Russian leader listened to Ms Pavlenko as she gave them the tour.
Later, the Italian billionaire is seen looking at a bottle identified to be from the vintage of 1891, and asked in English: "Is it possible to drink?"
The director replied: "Yes."
It is unclear what happened to that bottle, but Ukrainian prosecutors say the bottle they are concentrating on was worth more than $90,000 (£58,000). They say they are preparing embezzlement charges against Ms Pavlenko.
"This is one of the five bottles that constitute not only Massandra's or Crimea's heritage, but the heritage of all Ukrainian people,'' Nazar Kholodnytsky, first deputy prosecutor for Crimea told the Associated Press news agency in Kiev.
He said two bottles similar to the one allegedly consumed were auctioned in London in 2001 and one fetched nearly $49,700 (£32,000; €44,000).
"The funds went to the state coffers and supported the development of Massandra and wine-making in Crimea," Mr Kholodnytsky said.
Ms Pavlenko's predecessor as governor, Nikolay Boyko, was dismissed in February after Russian prosecutors filed fraud charges against him.
The new governor is herself wanted in Ukraine for treason after she voted in favour of Russian annexation in 2014.
"Now she's added one more crime to high treason," Mr Kholodnytsky said.
Mr Putin and Berlusconi enjoyed good personal relations when the Italian leader was in power, which they have maintained since he left office in 2011.