Test Text1 underline When doctors say there's little they can do to cure major wounds or even disease, many are now flocking to a very different kind of healer. One who cures not with medicine, but... See More
Test Text1 underline When doctors say there's little they can do to cure major wounds or even disease, many are now flocking to a very different kind of healer. One who cures not with medicine, but with touch. Faith healers. Many of them children. Raking in big bucks for a dose of hope. Here's ABC's Marianna Ve sometime Zoeller. Reporter: Faith can be intoxicating. It can fill the sick and suffering with an improbable hope that a 10-year-old will heal them with a simple touch. Aleni Santos, better known as the little missionary, has been drawing believers to her dad's church since the tender age of 3. Including Daniel nesak, who was shot in the head during a war halfway around the world, leaving the left side of his body partially paralyzed. After years of painful operations and therapy, Daniel is desperate for a miracle. So he traveled halfway across the world to Brazil where child healers are only part of a growing chorus of self-anointed miracle workers. Fueling an explosive spiritual movement 44 million followers strong. Evangelical christianity is the fastest-growing religion in Brazil. And it's seriously threatening the catholic church's historical dominance in the country. But with millions of souls and millions in donations at stake, critics say many bogus merchants of faith are turning huge profits with false promises. Pastor Eduardo is apparently a man of many talents. He won't just exorcise your inner demons, he also offers couples counseling. And even chiropractic care. I asked him if he thinks the catholic church can compete with his brand of christianity. And it turns out that gift is the only qualification he actually needs. Anyone can become a pastor? Anyone can become a pastor. Anyone can open a church? Can open a church. Reporter: The professor studies the business of of churches in Brazil. He explains that enterprising evangelical pastors benefit from its total lack of regulation, and he says that many pastors lure new worshippers with visions of prosperity and health. At pastor aruda's church, no matter how shameless the pit pitch -- believers line up to grease his palms with an offering. And in return he greases theirs with a splash of his own special holy oil. Members of these evangelical churches typically hand over 10% to 30% of their salary, not including offerings at mass. It's a very informal business. Because the money just goes directly from the wallets of the member to the wallets of the pastor of the church. So there's no control over the money? There's no control over the money. Reporter: He says that's made salvation a booming business. And nowhere is the growth more apparent than in this city. This is the main street here in this neighborhood, and we've been here about five minutes. We've seen over ten churches. By some estimates the city has more churches per square mile than anywhere necessarily Latin America. With this much competition everybody's trying to find a gillic to stand out. It's here we first meet aleni, the city's most popular child healer. This is her dad, pastor delta Santos. Do you think there are a lot of people that are skeptical about this, they think it's not possible that a 10-year-old, through her touch or her words, is able to be curing diseases like cancer and AIDS? He tells me critics will never believe. Seeing it is simply not enough. He says the moment a person receives the healing, they'll start to believe. And for years, those believers have knocked to his church with terminal conditions. But none, he says, are too severe for aleni. She's become a local celebrity here. Appearing on talk shows with her dad. He even hosts an internet radio show with listeners from around the globe. What do you feel when you're curing people? Reporter: At church aleni's dad warms up the crowd. As Daniel, the partially paralyzed gunshot victim, waits by anxiously. Reporter: And after receiving donations, he calls the ill and suffering to the front. For Daniel, this is the end of a long odyssey that began in a Croatian war zone. Reporter: And with that aleni works the line as she has hundreds of times before. All in perfect sync. As pastor Santos tests aleni's miracle, Daniel seems to be surrounded by success. Then he asks Daniel to grip the Mike stand with his paralyzed hand. His hand never opens. Afterwards, Daniel isn't disappointed. How do you feel now? I feel okay. I feel good. I feel warm at heart. I think I tried to open my heart. Did anything change in you physically? Are you able to -- I have -- no, I think it didn't change physically much. Reporter: He's not the only one with mixed results. That woman who miraculously walked? Only moments later, limping in pain. A lot of the people that came here today truly believed they were going to leave this store, leave the church, and be completely cured, yet that was not the case. The pastor tells me even though many are cured instantly, others experience gradual results. So you don't think you're giving people false hope or false promise in this. No. Reporter: He tells me no, this is about faith, and he doesn't expect everyone to believe. But Daniel for one is still holding out hope for a full recovery. For "Nightline," I'm Marianna van zollen.
This transcript has been automatically generated and may not be 100% accurate.