London, April 8 (IANS): This may be the first you're hearing of ayahuasca but the psychedelic drink -- a South American plant-based brew used for centuries in healing ceremonies -- can treat depression within hours of ingesting.

Brazilian researchers have published results from the first clinical test of a potential therapeutic benefit for ayahuasca.

Although the study included just six volunteers and no placebo group, the scientists say that the drink began to reduce depression in patients within hours, and the effect was still present after three weeks, the scientific journal Nature reported.

For the study, researchers led by Jaime Hallak, neuroscientist at the University of Sao Paulo, Brazil, gave one mild dose of ayahuasca to six volunteers who had been diagnosed with mild to severe depression.

After their drink, the participants sat in a quiet, dimly-lit room.

Physicians used standard clinical questionnaires to track their depression symptoms.

Improvements were seen in two or three hours -- a rapid effect as conventional antidepressants can take weeks to work.

"Three of the participants vomited, a common side effect of ayahuasca, but otherwise, the procedure was well tolerated," Hallak said.

According to Draulio de Araujo, neuroscientist at the Federal University of Rio Grande do Norte in Natal, Brazil, his team has already treated 46 (out of a planned 80) patients in a placebo-controlled study of ayahuasca and depression that began in January 2014.

"We hope to finish it by the end of this year," he noted.

"Aayahuasca can help one feel extra well, not just during the experience, but for up to days or weeks after," added Brian Anderson, psychiatrist at the University of California, San Francisco, who was not involved in the study but has published papers on the drink's potential.

Ayahuasca, a sacramental drink traditionally brewed from the bark of a jungle vine and the leaves of a shrub, contains ingredients that are illegal in most countries.

But a booming ayahuasca industry has developed in South America where its religious use is allowed.

Thousands of people each year head to rainforest retreats to sample its intense psychedelic insights, the report added.