The US military has declined direct comment on complaints by Saddam's lawyer that he was being force fed.
Saddam's trial for crimes against humanity is expected to be disrupted by the latest setback.
Saddam's defence is due to resume its summing up and a verdict has been expected from about September.
But Saddam's lawyers said they will boycott the trial following last month's killing of a defence lawyer, the third such death in Baghdad.
Sectarian violence
At least 42 people were killed when a suicide bomber detonated an explosives-laden minibus in a crowded Baghdad market and a bomb went off at a nearby town hall.
The attack on the Jamila market in the mainly-Shiite Sadr City district was followed by the explosion of a bomb placed in front of the area's administration.
Thirty-four were killed and 73 injured in the first attack which took place at 9.20am and eight killed and 20 in the second blast.
In Iraq’s northern oil centre of Kirkuk a car bomb exploded at midday in a market, killing at least 20 people and wounding more than 150.
The injured were taken to Kirkuk General Hospital for treatment.
Officials said the toll was high because the blast triggered fires in aged wooden shops, suffocating people.
Others suffered burns when the car bomb ignited chemicals stored in some shops.
It was the fourth car bombing this month in Kirkuk, where tensions are rising among Arabs, Kurds and Turkamen for control of the strategically important city.
Three days ago, a suicide truck bomber attacked an office of President Jalal Talabani's political party, the Patriotic Union of Kurdistan, killing five people and wounding 12.
On Thursday, another car bomb killed five people. A further car bomb on 13 July killed four people, including a child.
Peace plan
The violence came just a day after Iraqi leaders held the first meeting aimed at implementing a home grown peace initiative to end sectarian violence.
"This is an Iraqi initiative for those who are part of the political process," Prime Minister Nuri al-Maliki said and the speaker of Iraq’s parliament has urged US-led coalition forces not to interfere.
Mr Maliki said the Supreme Committee for National Reconciliation had already received positive signals from some of the insurgent groups battling security forces and US troops, including one led by a former army officer.
Parliament speaker Mahmud Mashhadani, a conservative Sunni Islamist said the committee would work to persuade groups which have opposed the political process to lay down their arms.
"We will contact those who oppose us on certain issues and will try to convince them and tell them the detail of the project to win their consent," he said.
Mr Maliki's government and the coalition have been struggling to contain a wave of sectarian violence in which rival Shi'ite and
Sunni death squads have killed hundreds of civilians around the capital in the past month.
With a month-old security operation apparently making little headway, Iraqi leaders hope the reconciliation committee will draw in those groups prepared to compromise, while isolating violent extremists.
Those who oppose his government's policies are free to do so, the prime minister said, but those who reject the peace process in favour of violence would be "pushed into a corner".