A woman is in critical condition and her two daughters have suffered kidney failure after she poisoned herself and three children with pesticide because she could not cope with the pressures of living, Chongqing Commercial News reported.

Tang Chengfang, 27, added pesticide to sugar and fed it to her two daughters, aged five and seven, and 8-month-old son in Dazhu county, Southwest China's Sichuan province while their father Li Heyuan was working away as a carpenter in Fuzhou, East China's Fujian province.

Li Chunhong, 7, the oldest child of Tang, receives treatment at a hospital in Chongqing, March 29, 2012. [Photo/Chongqing Morning News]

She then consumed the lethal concoction herself.

Tang Xuemei, a doctor at the Children's Hospital of Chongqing Medical University, said all three children are unable to eat food and can barely speak because their throat has been seriously damaged.

Li said in the second year of their marriage in 2004 his wife once wanted to commit suicide because she had a headache.

He didn’t blame his wife, only saying she might be too tired to bring up three children. "She may have depression," he said.

Li Heyuan, father of three children poisoned by his wife, is overwhelmed with sorrow at a hospital in Chongqing, March 29, 2012. [Photo/Chongqing Morning News]

Rao Chaoqiong, wife of Li's elder brother, said he thought Tang a good mother who treated her children well. "Even if she only had one yuan, she would spend it on her children," she said.

Li makes 3,000 yuan ($476) per month and until Tang gave birth to their third child last year they all lived together in Fuzhou.

After giving birth, Tang returned to Dazhou, to take care of their three children. Li spends several hundred yuan and sends the rest of his salary to his wife.

"I only want my family to be happy...I hope my children can make it. I don't know what to do without them," Li told local media.

Li has reportedly received more than 120,000 yuan in donations from the local government, a charity website and anonymous helpers.