By Agence France-Presse
Many drug addicts in communist Vietnam are forced to undergo up to two years of rehabilitation in treatment centres across the country, but rights groups have complained of poor conditions and overcrowding.
Addicts in the southern province of Long An forced their way out of a treatment centre on Sunday afternoon.
"Some patients hid in paddy fields or forests, some went onto the roads," Hoa Thanh Nien, deputy director of the provincial labour department, told AFP, saying many were upset they were spending the annual Tet new year holiday away from home.
Around 74 patients have since been recaptured or persuaded to return with authorities searching for the rest, he added.
Of the 169 patients at the facility, seven were voluntary admissions.
Vietnam's compulsory drug treatment centres have seen previous mass breakouts.
In November around 100 inmates escaped from a facility in southern Dong Nai during a riot in which police deployed tear gas.
Two weeks earlier some 450 addicts broke out of the same centre, flooding onto nearby roads and sparking panic among local residents.
There are more than 200,000 addicts in Vietnam, with heroin and methamphetamine being the main drug of choice, and almost 13,000 people are in treatment centres, according to official figures.