The U.S. Supreme Court said on Monday it would decide whether the federal government must allow the U.S. branch of a Brazilian-based religion to import a hallucinogenic tea for use as a sacrament.

The high court agreed to review a U.S. appeals court ruling that said the government could not prohibit the sacramental use of the tea because of a 1993 religious freedom law.

The U.S. Justice Department said that under the ruling the government must allow the importation and possession of hoasca tea for religious services, even though it contains an illegal, controlled substance that can be potentially dangerous.

Members of the religion, O Centro Espirita Beneficiente Uniao do Vegetal, believe the tea is sacred and that using it connects them to God. The tea is made from two plants that grow in the Amazon.

Founded in Brazil in 1961, the religion practices a blend of Christian theology and indigenous South American beliefs. It has about 8,000 members in Brazil.

In 1993, its leader set up a branch in Santa Fe, New Mexico, and it has about 130 followers in the United States.

In 1999, U.S. Customs inspectors intercepted a shipment from Brazil to the American branch of three drums labeled “tea extract.” U.S. agents then seized 30 gallons (136 litres) of the tea from the home of Jeffrey Bronfman, the head of the church’s U.S. chapter.

The tea contains dimethyltryptamine, or DMT, a controlled substance. The government said it had a high potential for abuse and was unsafe for use even under medical supervision, but attorneys for the religion said experts testified that sacramental use of the tea caused no harm.

The U.S. branch, Bronfman and several other members sued and sought an injunction to prevent the federal government from seizing the tea and to allow its importation and use in religious ceremonies.

Acting Solicitor General Paul Clement of the Justice Department appealed to the Supreme Court after the government lost before the appeals court.

“The… decision has mandated that the federal government open the nation’s borders to the importation, circulation and usage of a mind-altering hallucinogen and threatens to inflict irreparable harm on international cooperation in combating transnational narcotics trafficking,” he said.

Attorneys for the religion and its members urged the Supreme Court to deny the appeal. They said DMT was readily available in the United States from many sources, including grasses the government recommends to control roadside erosion.

The Supreme Court will hear arguments in the case and then issue a decision during its upcoming term that begins in October.