General Augusto Pinochet is in intensive care in a Santiago hospital after suffering a temporary interruption of blood to his brain.
The city's military hospital said the former Chilean dictator briefly lost consciousness and has "a minor loss of strength" in his left side. The symptoms are similar to that of a stroke but the hospital did not elaborate.
A retired army general had earlier in the day 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.
Pinochet was taken to hospital suffering from strong headaches and swollen legs.
He has been a frequent visitor to the hospital for a variety of health problems and earlier this month underwent four days of tests that showed he suffers from "moderate dementia".
Judge Juan Guzman last month indicted Pinochet but the Supreme Court subsequently dropped the charges because Guzman failed to first interrogate Pinochet.
The so-called caravan was a military party that toured several cities soon after Pinochet's bloody 1973 coup, dragging 75 political prisoners from jail and executing them. Eighteen 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.
Pinochet says the regional commanders, not himself, were responsible for what happened in their areas.