ON THE pavements around Parque da Luz in São Paulo’s old city-centre, skeletal rag-covered figures loll. This is the heart of the district known as Cracolândia (“Crackland”)—a few dozen streets used since the 1990s as an open-air crack den. As addicts moved in, law-abiding businesses and residents fled. Those who remain pay rock-bottom rents, pull down their shutters at 6pm and stay in at night.

São Paulo’s Cracolândia was Brazil’s first and is still its biggest. It is home to 2,000 addicts. But most Brazilian cities now have similar districts. Recent studies put the country’s crack-using population at 1m-1.2m, the world’s largest. In the past 20 years, as American consumers shifted to synthetic drugs, traffickers in the coca-growing countries—Bolivia, Colombia and Peru—sought new markets. Brazil shares long, porous borders with all three. Its growing prosperity ensured customers. The gangs born in its hellish prisons handled distribution.

Some city governments have used strong-arm tactics against the crack epidemic—with little effect other than to fill prisons, which have more than twice as many inmates as a decade ago. Last year a short-lived police offensive in São Paulo code-named Dor e Sofrimento (“Pain and Suffering”) forced addicts constantly to move on. That led to shambling parades through the city centre. The only lasting result was to expand their patch.

São Paulo city officials continue to talk tough, promising earlier this year to make it easier for judges to force addicts into treatment. That is popular. But it ignores both the vast unmet need for treatment, and the seeds of a more effective approach. So many desperate relatives of drug addicts have turned up at CRATOD, a drug-treatment centre overlooking Parque da Luz, that it has had to erect a marquee outside to handle them. The saddest sight on a recent visit was not the patients waiting for check-ups, counselling, art therapy and gym training, but the mothers being sent away empty-handed to seek help for their addict children nearer home. They are unlikely to find it: there are few public facilities on the city’s poor periphery.

Those who live close to CRATOD find that the promise of the swift locking-up of crack abusers turns out to be a mirage. Forced internment of addicts has in fact been legal in Brazil for a decade, but only for short periods and if a doctor thinks the patient poses an immediate, serious risk. What has changed at CRATOD are not those rules, but having a judge on call around the clock to speed up those rare cases. Four-fifths of those it has admitted this year have been day patients, free to come and go. Almost all in-patients were admitted voluntarily.

High drop-out rates are a big difficulty in treating crack patients. That makes forced internment tempting. But experience in Brazil and elsewhere, says Alfredo Toscano, the centre’s director, is that they often return to their old ways once released. For many, outpatient care is a better long-term bet: over its course, they must try to build a life without the drug. An on-site dentist is proving a big help in getting CRATOD’s patients to stay the course: the heat and acidity of crack-smoking destroy addicts’ teeth. Staff report that patients hope a rebuilt smile will help them to get a job or even a girlfriend.

The centre’s on-site police leave the task of approaching street users to medical staff and volunteers from churches and charities. “The job of police is to combat trafficking, protect health and social workers and keep the peace,” says Fernando Vieira, the state government’s secretary of security, who replaced a hardliner last year. “This is the first time there’s been such a co-ordinated approach anywhere in Brazil.”

Even some law-abiding residents of Cracolândia are trying to persuade the city that cracking down on crack has failed. They want a drug-treatment hospital to be built on an abandoned block. It could hardly make the district more of a draw for crack addicts than it already is, says Paula Ribas, the group’s president. “Any project here that doesn’t include drug treatment will fail,” she says.