YEREVAN, April 2 --  A mining cage drops deep beneath the Armenian capital, carrying asthma patients in helmets down into a salt cave clinic-an alternative treatment centre whose future is now at risk.

State funding for the speleotherapy centre in the Avan salt mine was recently cut as the small Caucasus nation rolls out a new universal healthcare system that does not cover alternative medicine.

The fate of the facility is a snapshot of a global debate over the effectiveness and role of alternative treatments in modern healthcare, a particularly pressing issue in developing countries.

Speleotherapy-where patients spend several hours a day in caves breathing mineral-rich underground air believed to reduce respiratory irritation-has...