The messages began to pop up on Chinese social media as the trade spat with the United States sizzled, urging people to boycott McDonald's and other American firms to "defend the economic Great Wall".
US President Donald Trump's tariffs on Chinese goods have roused nationalist sentiment in the world's second largest economy, where consumers have a long track record of spurning foreign products when political nerves are frayed.
Appeals to shun the likes of McDonald's, KFC and Apple's iPhone have appeared on the popular WeChat messaging app and the Weibo microblogging website in recent days.
"Compatriots, our motherland is going through a difficult time. We must unite to support our national brands and help defend the economic Great Wall!" read one message being circulated on WeChat. AFP was unable to verify the original source of the message.
On Weibo, a car salesman from northwest China's Gansu province wrote: "The US has fired the first salvo in this trade war. It's everyone's responsibility to boycott American goods!"
The Chinese government has hit back at the US tariffs and vowed to retaliate to any new measures, but President Xi Jinping and Trump delivered conciliatory words this week that raised hope of a negotiated solution.
China's state-run Global Times tabloid has encouraged the government to take a tough stance, with an editorial last week saying China should fight with the same spirit as during the Korean War -- one that "fears no sacrifice or loss".
"Chinese living across the globe have considerable purchasing power. We can cause a lot of damage to the US economy," wrote one reader in the article's online comment section.
But it may be tough to convince Chinese people to give up American brands that have become ubiquitous in streets and shopping centres across the vast country.
The calls for boycotts certainly didn't ruin the appetite of the lunch crowd at a McDonald's in downtown Beijing this week, just a stone's throw away from the Ministry of Foreign Affairs.
"I also received these messages, I just delete them," said diner Wang Zhiyi, who was wolfing down a double cheeseburger with fries and a coke. "These people (who share such messages) just want to cause a ruckus."
This isn't the first time American products have been targeted by boycotts.
Photos of individuals smashing their iPhones emerged on social media in 2016, purportedly to denounce US support for the Philippines in a territorial dispute with China over the South China Sea. Protesters also shouted slogans in front of a dozen KFC outlets.
But Ben Cavender, an analyst at Shanghai-based China Market Research Group, said he did not expect a boycott to gain much traction this time.
"Despite online slogans, surveys show that service brands that mostly employ Chinese nationals are viewed more positively," Cavender told AFP.
At the Dunkin' Donuts outlet across the road from the McDonald's, bank employee Gao Junya sat sipping her afternoon coffee with a friend.
"Do you think this donut is a symbol of American overreach and imperialism?" she asked, biting into a gooey Boston Cream. "Small groups on social media are just trying to put up smokescreens."
Watering down wine
Although many were quick to brush aside nationalist slogans, American wine has taken a hit.
"I've had a couple of corporate clients who've said they'd prefer to switch from a US wine to something else (for official events) in recent weeks because they are conscious of the image they are projecting," Jim Boyce, a Beijing-based wine consultant, said.
According to the California Wine Institute, China was the fifth biggest importer of wine from the Golden State in 2017.
While China's new 15 percent tariff on US wine, announced last week, is threatening to make it less price-competitive, the nationalistic fervour could deal an even harder blow, Boyce said.
"The biggest concern is whether this negativity would turn into a long-term sentiment," he said.
Other countries have felt the pain of running afoul of China.
Beijing hit South Korea with a string of measures against businesses last year after Seoul let the United States install an anti-missile defence system in its territory to defend against North Korean threats. China sees the hardware as a threat to its own security.
French retail giant Carrefour became the target of a string of protest ahead of the 2008 Beijing Olympics after pro-Tibet activists disrupted the Olympic torch relay in Paris.
And Norwegian salmon was left rotting in Chinese warehouses after the 2010 Nobel Peace Prize, based in Oslo, was awarded to democracy advocate Liu Xiaobo, who died of cancer while still in custody last year.