“Like beef bouillon that fell on a brewer’s floor.”

With that, Jimmy Fallon’s Tonight Show broke the hearts of millions of Australians and sent American-Australian relations hurtling back 50 years.

• Yep, vegemite chocolate is now totally a thing
• The next global food phenomenon is … toast?

On Monday night’s show, Fallon and his sidekick announcer Steve Higgins were dared by two young Aussie fans to try the delicious yeasty spread. It didn’t go so well.

“I think Steve Higgins should try Vegemite because he doesn’t really do anything,” said the letter from Charlie, 7, and Jed, 4, as part of the regular ‘Kid Letters’ segment.

Higgins bravely (and naively) took a giant dollop of Vegemite and spread it (without butter) on a piece of bread (untoasted) before spitting it out immediately.

Any Australian will know this is all wrong.

“What does it taste like, man?” Fallon asked, laughing as Higgins washed his mouth out with coffee.

“I think it’s not for the American palate,” he said.

The 40-year-old comedian raced over and tried it for himself before physically gagging.

“It’s like waves, it comes in waves,” he joked.

“Not bad. It taste like beef bouillon or something,” he then added.

Higgins was far more scathing.

“It tastes like beef bouillon that fell on a brewer’s floor.”

On Twitter, Vegemite was a good sport about the sledging, telling Jimmy Fallon that “not for American palates” might become their new slogan.

Some Americans sympathised with Fallon, calling it “seriously the worst”, but Australians, including the ABC, stood firm and told the 40-year-old he had just eaten it all wrong.

.@FallonTonight we feel so misunderstood #acquiredtaste #FallonTonight @jimmyfallon

— Vegemite (@Vegemite) May 12, 2015

.@FallonTonight at least they tried before they denied this taste sensation 😉 #SpreadTheLove #acquiredtaste #FallonTonight

— Vegemite (@Vegemite) May 12, 2015

.@FallonTonight “Not for American palates” might become our new slogan 😉 #FallonTonight @jimmyfallon — Vegemite (@Vegemite) May 13, 2015

@jimmyfallon #Vegemite is seriously the worst. I tried some on my honeymoon in NZ and projectile vomited back in my hotel room. #goodtimes — Tanya (@TanyaTerrific) May 12, 2015

If you eat @Vegemite like that @jimmyfallon of course it’s going to taste putrid! No one eats it like that! Toast w/ butter. #FallonTonight — Tom Lut (@Toot182) May 12, 2015

@jimmyfallon To start out with vegemite, you want to spread it thinly, on top of buttered toast. You spread it far too thickly, that’s all. — suse cairns (@shineslike) May 12, 2015

@jimmyfallon Vegemite isn’t so bad! Try it with butter, it’s much better — ABC2 (@ABC2) May 13, 2015

Just made one of the dudes visiting from the London office try Vegemite ala @jimmyfallon. He was not impressed. It was awesome. — Freya Noble (@freyanoble) May 13, 2015

@jimmyfallon you ate Vegemite all wrong! No wonder you didn’t like it. Toast, butter and then a little bit of vegemite! #sillyamericans — Shannon Diedrich (@shadiexo) May 13, 2015