Giovanni Trapattoni will remain in hospital overnight, the Football Association of Ireland have confirmed.
The 71-year-old Republic boss was taken to Dublin's Mater Hospital in the early hours of the morning suffering from food poisoning ahead of Wdnesday evening's friendly against Argentina at the new the 50,000-seater Aviva Stadium.
An FAI statement read: "Giovanni Trapattoni has undergone a number of tests today in the Mater Hospital and all of those test results are normal to date."
It continued: "He will be kept in overnight and will be reviewed by his consultant in the morning.
"His condition remains stable and not serious."
Assistant Marco Tardelli, who took training on Tuesday, was hopeful Trapattoni would be well enough to take charge.
He said: "I think everything is okay and he will be in the dugout. He is very strong."
The FAI also confirmed Stoke midfielder Liam Lawrence has returned to his club after picking up a groin strain in training.