Leading Chinese dissident, Gao Zhisheng, has been "utterly destroyed" after three years in jail, says his international lawyer, Jared Gensher.
Mr Gao - who was released from prison last week - was emotionless, "basically unintelligible" and had lost teeth through malnutrition, Mr Gensher said.
As a prominent human rights lawyer, Mr Gao had defended China's Christians and followers of the Falun Gong movement.
He is alleged to have suffered physical and psychological abuse in jail.
As well as losing many teeth, Mr Gao's daily ration of cabbage and a single slice of bread had caused him to lose 20 kg in weight, according to a statement by US-based advocacy group, Freedom Now.
The group said he had been confined to a cramped cell, with very little light, and had been largely deprived of human contact until his release.
Freedom Now said Mr Gao's wife, Geng He, had spoken to her husband and was "completely devastated" by what the Chinese government had done to him.
"The only thing I feared more than him being killed was his suffering relentless and horrific torture and being kept alive," she is quoted as saying.
Ms He has urged the Chinese government to allow Mr Gao to seek treatment in the United States, where she and their two children have been living since 2009.