"Two ICRC representatives, including a doctor, visited Saddam Hussein on Saturday in Iraq and were able to stay with him long enough for a physical and mental evaluation," the organisation's spokeswoman Nada Dumani said from Amman.
"In accordance with its rules, the ICRC is unable to give any indication about the condition of Saddam Hussein. The ICRC, following this visit, as in the case of all [Iraqi] prisoners, will report directly to the [US-led] coalition," she added.
Another spokesman in Amman said the Red Cross would deliver a message from Saddam to his family.
Asked whether it would be a written message, the spokesman Muin Kassis said: "Yes, there is a special form that he writes on - only family news - and it will be delivered to the family."
US forces captured the former president on 13 December from a hole on a farm in a village close to his hometown of Tikrit, north of Baghdad. US authorities formally gave the ICRC the green light to visit him on 14 February.
Top US-led occupation spokesman Dan Senor confirmed to CNN television that ICRC officials had visited Saddam, but that in the spirit of the Geneva Convention it would be "inappropriate" for him to comment further.
The US on 9 January formally accepted Saddam was a prisoner of war, angering the US-appointed Iraqi Governing Council, which was demanding he should stand trial in Iraq for crimes against humanity.
"In accordance with its rules, the ICRC is unable to give any indication about the condition of Saddam Hussein"
spokeswoman, ICRC, Amman
The ICRC oversees the Third Geneva Convention, an internationally recognised and binding set of rules which guarantee minimum standards of treatment for prisoners of war and detainees, including the right to visits from its aid workers.
It forbids physical or mental torture, or "any other form of coercion ... to secure from them any kind of information whatever".
Visits include checks on accommodation, food and health care as well as a prisoner's treatment by guards.
Red Cross workers also insist on carrying out a confidential interview with the prisoner, without the direct presence of guards or authorities and out of earshot.
ICRC officials and legal experts have repeatedly emphasised the Geneva Conventions would not stop Saddam or any other Iraqi detainee facing trial on possible charges of war crimes.
Some 6700 security prisoners are being held by the US-led occupation in Iraq. The ICRC visited about 500,000 detainees in 70 countries last year.