A US federal appeals court has ruled that a California woman who uses marijuana to ease a number of ailments can be prosecuted on federal charges.
Eleven US states allow medical marijuana on doctors' orders
Angel Raich pre-emptively sued the government for the right to use cannabis when legal drugs had failed.
Her doctor testified that she could die if she stopped taking marijuana. She has an inoperable brain tumour.
The Supreme Court ruled two years ago that federal drug laws override those in 11 states allowing medical cannabis.
Eleven states, including California, allow the drug's use if doctors recommend it.
"Today I found out I'm basically a dead man walking," said Ms Raich, a 41-year-old mother of two in Oakland, California.
As well as the brain tumour, she has scoliosis, chronic nausea and other medical problems.
She said she takes marijuana every two hours to ease her pain and boost her appetite and said she would continue to do so.
"Today the court said I don't have the constitutional right to basically stay alive," she said.
The three-judge appeals panel acknowledged that although support for the medical use of marijuana was growing, the US was not yet at the point where "the right to use medical marijuana is 'fundamental' and 'implicit in the concept of ordered liberty'."
Ms Raich said she would lobby Congress to change the 1970 Controlled Substances Act that bans marijuana.