Medical sources on Friday said Pinochet, 87, had a dizzy spell and fell in the bathroom of his coastal resort home, 110km west of the Chilean capital.
Pinochet, who suffers from diabetes and age-related ailments, was hospitalised twice previously this year.
The former general has faced some 300 charges related to the deaths and disappearances of more than 3000 of his political opponents during a brutal 17-year military reign, which lasted until 1990.
On 11 September 1973, Pinochet led a military coup backed by the CIA, which saw the overthrow and led to the death of democratically elected Chilean President Salvador Allende.
A Commission for Truth and Reconciliation set up under President Patricio Aylwin in 1990, issued a report, based on nine months of testimony and research, which described several stages of repression under Pinochet.
In the weeks after the coup, thousands of Chileans sympathetic to the socialist government were detained. Many were tortured, and several hundred were tried and executed by military war tribunals.
In the next stage, the army's secret police squads waged a "systematic campaign to exterminate" leftist dissidents from 1974 to 1977, the report states.
Inside clandestine prisons, people were tortured with electric shocks, choking, confinement and even animal rape. There were 957 victims who never reappeared and are presumed dead.
Pinochet was arrested in London, in 1998, on torture and genocide charges on a warrant issued by a Spanish judge.
British authorities later released Pinochet after doctors ruled him physically and mentally unfit to stand trial.
He was also declared by Chile's Supreme Court as mentally unfit to stand trial on murder and kidnapping charges related to atrocities carried out under his rule.