The Higher Power singer is under "strict" doctor's orders to rest for three weeks and so the band have cancelled eight concerts in Brazil as part of their Music Of The Spheres world tour.
Coldplay said in a statement: "Due to a serious lung infection, Chris has been put under strict doctor’s orders to rest for the next three weeks.
"To everyone in Brazil who was looking forward to these concerts, we’re extremely sorry for any disappointment and inconvenience, and we’re so grateful for your understanding at this challenging time where we need to prioritise Chris’ health.
"We’re optimistic that Chris will return to good health after the prescribed medical break and look forward to resuming the tour as soon as possible.
To everyone affected, please accept our sincere apologies, and thank you as always for your love and support."
The tour is due to continue in Argentina on 25 October until 8 November, before taking a break and continuing in Europe in May 2023.
They now plan to reschedule to the Brazil dates in Rio de Janeiro and Sao Paulo for early 2023.
Coldplay expressed "deep regret" for the cancellation.
They urged fans to "hold onto your tickets", for rescheduled dates to be confirmed soon, but also promised to honour refunds.
Martin, 45, is the lead singer of the globally successful band, who are famous for their lavish live shows.
The Rush Of Blood To The Head singer recently revealed that drummer Will Champion has to approve his more eccentric stage show ideas, to keep him in check.
Martin said: “We have ideas people and filters in the band.
“Without both we couldn’t operate. For every idea that you see on stage there has been about 51 that Will said, ‘No way’. But that is how it works. He has to feel it. Once he feels it, we do it."
Martin has two children, Apple and Moses, with ex-wife Gwyneth Paltrow.
He has been dating Fifty Shades Of Grey star Dakota Johnson since 2017.
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