Cerys Matthews: Expected to take another week to recover
The Welsh band has pulled out of three festivals since singer Cerys Matthews was admitted to a rehabilitation centre almost a week ago.
They cancelled a gig at BBC Radio 1's One Big Sunday in Plymouth on Sunday, and have also pulled out of this weekend's Witness Festival in Dublin.
The band's record company said Cerys was expected to take another week to recover.
A statement issued when the singer went into rehab said she was "receiving treatment for exhaustion and a recurrent asthma complaint - both of which have been exacerbated by drinking and smoking".
The band's September tour would not be affected, a spokeswoman said on Tuesday.
Reef will replace them as headline act at Guildford.
Matthews, 32, has had a hectic schedule promoting Catatonia's new album Paper Scissors Stone.
She will now "take a step back from ongoing promotion" of the album, according to her record company Blanco y Negro / WEA.
Matthews has spoken recently of the "depression" which led to the singer losing her self-belief.
The problem led to an extended silence for the band until their latest release.
In an interview with Q magazine in June, Matthews spoke candidly of the strain of pop stardom and touring.
The singer admitted to having suffered a breakdown last year after becoming "worn out" by the band being catapulted into the public eye.
"That doubt I'd felt grew, grew into times of doom and gloom," said Matthews.
The singer said the "turning point" happened at an arena concert when the band began a song and she could not remember the words. "The fear set in," she said.
"I've never in my whole life doubted me, doubted my part in this band, until that point. "
Catatonia's latest single, Stone By Stone, was relaesed last week.