Police across the United States were on the lookout yesterday for a mother and son who fled their home in Minnesota to elude court-ordered chemotherapy for the boy, who has been diagnosed with Hodgkin's lymphoma.

An arrest warrant for Colleen Hauser was issued after she failed to appear for a court hearing on the condition of 13-year-old Daniel.

Her husband told the judge she disappeared with Daniel the previous evening and he did not know where they were.

On Tuesday, Hauser took her son to their family doctor who said that a court-ordered x-ray had shown his tumour was growing and needed urgent treatment. While Hodgkin's lymphoma is a serious condition, it is often effectively tackled with chemotherapy.

The family have been declining the treatment for the teenager for religious reasons. They subscribe to the teachings of the Nemenhah Band, a group that believes in natural alternatives to modern medicine.

"I know many people who have had cancer, they did chemo, it would come back," Anthony Hauser, the boy's father, told the Star Tribune of Minneapolis yesterday. "They did the chemo again and again and they are all in the grave. Chemo isn't foolproof."

He acknowledged he was disappointed by his wife's actions, saying they had agreed to appear in court together on Wednesday.

In testimony, the boy, who has learning disabilities, said if anyone tried to make him undergo chemotherapy, "I'd fight it. I'd punch them and I'd kick them."