Russia has banned imports of Borjomi mineral water from Georgia, fuelling Georgian anger sparked by an earlier ban on the Caucasus republic's wines.
Borjomi has enjoyed big sales in Russia for years
The head of Russia's chief public health watchdog, Gennady Onishchenko, said inspectors had found that Borjomi failed to meet water purity standards.
"I therefore revoke from 7 May... Borjomi mineral water safety certificates," he said.
Borjomi has been popular for years in the former Soviet Union.
Georgia's Agriculture Minister Mikhail Svimonishvili reacted angrily to the Russian ban on Friday, saying "It's quite clear that today Russia is fighting against everything Georgian".
"Borjomi is one of the best brands of mineral water in the world," he insisted.
Russia's Itar-Tass news agency says Russian inspectors recently found several large consignments of fake Borjomi and 25,000 bottles of the mineral water were taken off shop shelves in Moscow alone last month.
Russia has blocked imports of Georgian and Moldovan wines and spirits since 27 March, again citing public health concerns.
Georgia's Western-leaning government has accused Russia of waging economic warfare.
Russia has been by far the biggest market for Georgian wine, and Tbilisi is now stepping up efforts to export wine to other countries.