General Augusto Pinochet has been taken to a military hospital suffering from strong and persistent headaches.
His illness occured only hours after another general accused the former Chilean dictator of being responsible for dozens of political killings.
Pinochet was taken to the Santiago Military Hospital in a motorcade from his country home southwest of the capital.
The vehicles entered the hospital compound and Pinochet was then rushed inside in a wheelchair.
Earlier, a retired army general accused Pinochet of being responsible for dozens of political killings arising from the Caravan of Death, a case that has the former dictator on the brink of facing trial.
The so-called caravan was a military party that toured several cities soon after the bloody 1973 coup, dragging 75 political prisoners from jail and executing them. 18 of the victims remain unaccounted for.
Retired General Joaquin Lagos appeared on state television saying that the chief of the caravan, then General Sergio Arellano, was acting as a direct representative of Pinochet at the time of the deaths.
Lagos, who was commander of the northern military region where most of the executions occurred, said that when he confronted Arellano, he produced a document "showing that Pinochet had appointed him as his personal delegate".