The American at the centre of the trial of Myanmar opposition leader Aung San Suu Kyi is in hospital in Yangon after collapsing in prison.
John Yettaw, whose swim to Ms Suu Kyi's lakeside home in May breached the terms of her house arrest, was taken to Yangon General Hospital on Monday.
His lawyer says he does not know what caused the collapse, but says his client suffers from epilepsy, diabetes and heart trouble.
The 54-year-old appeared in court alongside Ms Suu Kyi, charged with immigration offences and under a municipal law that bans swimming in a non-swimming area.
A legal source says a verdict on the trial, due on 11 August, could be delayed further if Mr Yettaw does not recover in time.