Liam Gallagher (left) is "resting up" before the band's next gig on Friday
Oasis pulled out of their headline slot at the V Festival in Essex after Liam Gallagher contracted viral laryngitis.
The singer was advised by doctors not to perform, a statement said. Fans booed as Snow Patrol, who stepped up to fill their slot, mentioned their name.
Oasis were the main attraction on the line-up for many at the festival.
Deborah Faux from Braintree, Essex, said: "I only came here to see Oasis and I'm really disappointed. That's put a real dampener on my whole weekend."
Andrew Slater, 21, from Ipswich, added: "I'm pretty gutted. It's annoying that they've pulled out. For loads of people who are here, they were really looking forward to seeing Oasis."
Georgina Wilson said she was "really disappointed", adding: "I paid £165 for the weekend, mainly to see Oasis and then they drop out."
Snow Patrol moved up to the headline slot and performed two Oasis covers
A statement from the band said: "After a year of being on the road this is the first performance to be lost to a band member's illness, so naturally we are all gutted."
The band performed at the V Festival's other site in Staffordshire on Saturday.
But Noel Gallagher wrote in his blog that he "didn't enjoy it one bit" and was not feeling well himself.
"Don't feel too clever," he wrote after the show. "Outrageous stomach ache. Feel like I'm coming down with summat.
"Might have to get the doctor out in the morning. Hope it came out of the speakers ok. Gutted. Oh well, there's always tomorrow."
The Essex performance was due to have been the last UK gig of Oasis' world tour, which began in Seattle 12 months ago.
The statement said Liam Gallagher was now "resting up" and is expected to be fit for their next show, in Paris on Friday.
Amy Winehouse made a surprise live comeback with The Specials at V
Fans gave a frosty reception when Snow Patrol singer Gary Lightbody paid tribute to "the mighty Oasis".
But the crowd sang along with gusto when the band covered Oasis classics Wonderwall and Champagne Supernova during their encore.
Psychedelic US rockers MGMT headlined a different stage in Essex on Sunday, opening with a version of Oasis' Live Forever and carrying a cardboard cut-out of the absent Liam Gallagher.
The cancellation came amid speculation over the band's future after Liam Gallagher admitted he and his brother Noel rarely speak, do not travel together and only see each other on stage.
"He doesn't like me and I don't like him, that's it," Liam told NME magazine earlier this week.
Oasis had to reschedule a tour date in Dusseldorf, Germany, earlier this year.
Fans enjoyed scorching weather at both festival sites
Liam Gallagher was found to have fluid on his vocal chords after complaining of a sore throat and was advised to rest for 48 hours.
Las Vegas indie heroes The Killers sat alongside Oasis at the top of the V Festival bill, with bands playing both sites during the weekend.
Amy Winehouse made her first UK appearance for almost a year when she joined ska legends The Specials in Essex on Saturday.
Winehouse gave a rendition of their tune You're Wondering Now and sang backing vocals on The Specials' hit Ghost Town.
Other acts attracting big crowds over the weekend included Lady GaGa, playing the last European dates of her tour, Mercury Prize winners Elbow, Lily Allen, Paolo Nutini, Dizzee Rascal and Katy Perry.
Fans enjoyed scorching weather at both sites, with 85,000 revellers at each location.