Local media outlet Vientiane Times reported the operators of the hostel have been detained for questioning.
A fellow United Kingdom backpacker, who wished not to be named, had two “free vodkas” at Nana Backpackers shortly before 3pm on November 9 but became sick, according to the Herald Sun.
They were served by a Toan, a bartender who told Laos police the vodka he poured came from a factory.
He said he had not added anything or watered it down – even pouring a glass for himself and taking a drink himself to prove it was safe.
The backpacker told the Herald Sun she suffered temporary blindness, spent a day vomiting, and had a resting heart rate of 170 beats per minute when she finally received medical help.
An average resting heart rate for a 21-year-old woman is 70 beats per minute.
She said it was difficult to communicate with the doctors, who spoke little English and “thought I was drunk”.
She said her heart rate lowered after a saline drip and hospital staff discharged her with nausea medication.
Bethany Clarke, a UK tourist who was hospitalised alongside her friend and victim Simone White, says her liver began to “shut down” and she underwent “many infusions and tablets and days of recovery”.
“Six of us who drank from the same place are in hospital currently with methanol poisoning,” she said in social media post.
Clarke warned backpackers to avoid all local spirits as they are “so not worth it”.
The Laos Government vowed to “bring the perpetrators to justice” in its first public statement on the poisonings on Saturday.
Officials said they were “deeply saddened” and extended their “deepest condolences” to the victims’ families.
“The Government of the Lao PDR has been conducting investigations to find causes of the incident and to bring the perpetrators to justice in accordance with the law.”
American victim James Louis Hutson, 57, was found dead inside his room at the Nana Backpackers on November 13.
The Vientiane Times says hostel workers entered his room after realising he had not left all day and found him unconscious.
Police found four empty beer bottles and two empty vodka bottles in Hutson’s room, according to the report.