Two members of a family of five have died after the family suffered food poisoning symptoms Tuesday in southwest China's Guangxi Zhuang Autonomous Region, police said Wednesday.

They complained of headaches and nausea and began to vomit three hours after having dinner at home on Monday night, police said.

They sought treatment at a township-level clinic early Tuesday as one person was unconscious, doctors said.

The family was immediately transferred to a bigger hospital because of the severity of the symptoms, but a 54-year-old man and a 35-year-old woman, believed to be the man's daughter-in-law, died later.

The other three remained critically ill.

Government officials and police are investigating the cause of the incident.