CECILIA HEYDER has breast cancer. She also has systemic lupus, a disease of the immune system. She’s had a mastectomy, radiotherapy and chemotherapy. She has taken many painkillers, often with side effects as bad as her symptoms. Last year, in desperation, she asked a doctor what else she could take to relieve her agony. He took out a pen and drew her a cannabis leaf. “It was as if he didn’t dare speak the drug’s name,” Ms Heyder recalls.

A 48-year-old mother of two, Ms Heyder had only dabbled with cannabis as a teenager. But she got hold of some leaves and used them to make tea. The result was startling. It was far more effective than any conventional painkiller she had used.

Inspired by her illicit experiment, Ms Heyder looked for Sativex, a cannabinoid medicine, but it was unavailable in Chile. She persuaded the government to let her import it; the drugs arrived from Europe in September. The Chilean authorities say it’s the first time a cannabis-based treatment has been legally brought to Latin America.

But Sativex is pricey. It costs Ms Heyder $2,000 a month. When her stash runs out she will have to buy more cannabis on the streets. “I don’t want to go back to the fear of being arrested,” she says.

In view of the cost of cannabinoid medicines, campaigners in Chile are arguing for the right to make cheaper alternatives. In September they won a ground-breaking victory. The Daya Foundation, a local not-for-profit outfit, was allowed to grow cannabis on land in La Florida, a district of Santiago. It will be used to make a painkiller for 200 cancer sufferers. The seeds were sown on October 29th. Blessed by the state, it is the first such project in Latin America. Uruguay made waves by legalising recreational marijuana use; now Chile is blazing a trail for the medicinal kind.

Nicolás Dormal, Daya’s co-founder, says teaming up with the University of Valparaíso and a respected cancer clinic helped secure approval. The project includes a clinical study of cannabis as a painkiller. La Florida’s mayor, Rodolfo Carter, is on board. “I’ve had a few jokes about the mayor growing his own pot but in general the reaction of local people has been awesome,” he says. “They realise this is not about personal use of marijuana...[but] providing people with a natural, healthier and cheaper treatment for their pain.”

The project may soon expand to help with other ailments. Many Chileans grow marijuana illegally and use it to combat epilepsy. A group of mothers produce the stuff for their epileptic offspring.

Not everyone approves of marijuana as a medicine. Doctors and psychiatrists warn that it is habit-forming. The World Health Organisation says it impairs learning and can worsen schizophrenia. The WHO accepts that cannabinoids can have positive therapeutic effects but says more research is needed into their benefits.

But people like Cecilia Heyder cannot wait; she has only months to live. Having seen how cannabis works, she will use it whether it’s legal or not. Fear of arrest is only a slight deterrent when you’re dying.

Faced with such realities, there is little point in prosecuting people who use cannabis to reduce pain. Canada and at least eight European countries allow the marketing of cannabis-based medicine; now the trend may be starting in the southern hemisphere. For people with little else to celebrate, that is good news.