Pope Benedict XVI has visited a drug treatment centre near the shrine city of Aparecida in Brazil on the third day of his five-day tour of the country.
Some 6,000 people gathered to see the Pope at the drug clinic
On Friday the Pope canonised Brazil's first native-born saint, Saint Antonio Galvao, at a huge open-air Mass.
He used the occasion to decry "an age so full of hedonism".
The Catholic Church is trying to reinvigorate itself in Latin America. It has lost millions of faithful in recent years to evangelical churches.
'Ambassadors of hope'
About 6,000 people gathered outside the Fazenda da Esperanca (Farm of Hope) drug centre near Aparecida, east of Sao Paulo, to greet the Pope.
He urged recovered addicts to be "ambassadors of hope" and said the clinic bore testament "to the Gospel of Christ amid a consumer society far removed from God".
At the clinic, which claims to have an 80% success rate and is run by Franciscan friars, patients receive spiritual guidance while working on a farm as beekeepers, milking cows or tending apple orchards.
Aparecida is also home to Our Lady of Aparecida - a statue of a black Virgin Mary and the patron saint of Brazil.
The Pope will recite the Rosary and meet Catholic officials at the Basilica of Aparecida later on Saturday before opening a Latin American bishops' conference in the shrine city on Sunday.
On Friday, in Sao Paulo, the Pope met Brazil's 430 bishops to discuss ways to reverse the church's decline in the country, the world's most populous Catholic nation.
He acknowledged that the Church was experiencing "difficult times".
"No effort should be spared in seeking out those Catholics who have fallen away," he said.
In 2000, 74% of Brazilians were Catholics, compared to 89% in 1980. Many have turned to evangelical Protestant faiths, which now make up 15% of the population.
The Pope said people who were most vulnerable to the "evangelical sects" were "easily influenced because their faith is weak, confused, easily shaken and naive, despite their innate religiosity".
Earlier, as he canonised the new Saint Antonio Galvao, Pope Benedict urged the gathered to follow the example set by the new saint by helping the needy "in an age so full of hedonism".
He lauded Saint Galvao as a model of rectitude and humility, and criticised elements of the media that ridiculed the sanctity of marriage and virginity before marriage.