'We thought it was just a bad hangover. In reality, my best friend was dying.'

When asked to recall what her best friend Simone White was like, Bethany Clarke admitted she struggles with the question. She's still grappling with the loss of her "kind and thoughtful" friend, who she'd known since childhood.

"Simone had everything going for her. She loved travelling and meeting new people. She had a zest for life," Bethany told Mamamia.

"I would hate for her to have died in vain and for this to happen to someone else. I'd never forgive myself."

Bethany and Simone were three days into a "bucket list trip" together when they made the decision to go drinking at the Nana Backpacker Hostel in Laos last November.

They had no way of knowing the shots were laced with methanol, a tasteless and dangerous substance.

They had no way of knowing it, but the small amount would be enough to kill Simone.

Still processing her grief, Bethany is determined to warn others about the invisible danger that claimed not just Simone's life, but the lives of five other travellers in Vang Vieng that night, including Australians Holly Bowles and Bianca Jones.

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'Something wasn't right'.

Bethany told Kate Langbroek on Mamamia's No Filter podcast the friends hadn't planned on going to Laos originally.

"It was just supposed to be a fun holiday, really," she said. "Initially, the plan wasn't actually to go to Laos at all. It was just to be Cambodia, and Simone kind of encouraged me to go with the plan of it also being Laos, because we were only supposed to be there for four days, and then this happened on the, I think, the third day."

On that third evening, Bethany and Simone made the decision to go drinking at the Nana Backpackers hostel. There, the friends would have five to six shots, over two and a half hours.

Bethany recalled the hostel was relatively quiet, with around 30 people "no more" there.

"We actually felt that there wasn't that much going on," she said, adding the friends played card games and phones on their mobiles.

"I don't recall it being particularly loud. And I think that's also why, at 10 o'clock, when the drinks finished, the happy hour drinks finished, everybody just went somewhere else, because there wasn't an amazing atmosphere. So yeah, it's supposed to be a party hostel, but I didn't get that particular vibe that night."

Bethany said the methanol-laced alcohol they drank "looked like regular" alcohol. Nothing about its appearance or taste made her "think it could be anything bad".

Later that night, Bethany started noticing strange signs.

"I went to bed at 10:45pm because I felt quite fatigued, and I don't know if that was jet lag or methanol setting in," she said.

Bethany (left) lives and works in Brisbane, while Simone (right) was a lawyer based in the UK. The friends were seasoned travellers and wanted to meet up halfway between the two countries for a holiday. Image: Supplied.

"We woke up the next morning feeling vaguely the same," Bethany said. "We just felt a 'bit off', and we couldn't really work out what was wrong with us."

Bethany noticed both her and Simone's appetite was off at breakfast. Another strange sign, as Simone would normally be "ravenous" in the morning.

The two girls forced a meal down and they, along with their other friend, decided they were feeling well enough to proceed with a pre-booked kayak tour along the picturesque Blue Lagoons.

Once the tour began, things got even worse.

"Simone and I couldn't go on the same kayak together. Both of us felt too weak to be on the same one," Bethany said.

"We went on different kayaks and had to lie down in the back of them, not really being able to paddle with our arms because we felt too weak.

"I had to just lie down and look up at the sky and wait for the tour to end."

After the hour-long tour, the friends returned to the hostel and attempted to eat something to feel better.

Around 1:30pm, while on a minibus ride, the friends realised something serious was happening.

"As soon as we got on, I fell asleep," Bethany said.

An hour into the journey, their friend called out to Bethany as Simone had been sick, so they got off the bus.

"When we got off, I then fainted. Simone was sick, and we worked out that something was not quite right."

The driver rushed the trio to the closest public hospital.

This photo was taken the day after Simone and Bethany were poisoned. Image: Supplied.

Navigating a foreign hospital system.

As their friend rushed inside the hospital to get help, Bethany sat outside with Simone and questioned, in a dazed state, why they were even there. She thought the reaction was "a bit over the top."

"We seemed to be in a state of cognitive decline, we couldn't think rationally," she said.

Soon the medical tests would start.

An hour into the visit, at about 6pm, Simone came into Bethany's room, and was given a bed. Bethany remembers checking her friend's heart rate on her watch. It was 82 beats per minute, which is considered the normal range for those with faster heart rates.

About 45 minutes after that, Simone started going into "respiratory distress".

"She started gasping for air around 8pm. She wasn't able to talk to me because of how bad it was, and the doctors were asking 'could it be amphetamines?', I think because she was agitated," she recalled.

Simone was rushed to the Intensive Care Unit (ICU), where she was given oxygen and fluids.

Their friend, who was also struggling with some symptoms of methanol poisoning, started researching private hospitals and by 11:15pm they were checked into a new facility.

"They got me to sign a lot of forms, and they just said, 'we will do what we can to save her life,' but I had to let them take her," Bethany said.

Bethany tried to sleep, but she would be woken to pay for tests, to sign more forms. Occasionally, she would be updated on Simone's condition.

They were moved into ICU when doctors tested their blood and found it was acidic. They were given sodium biocarbonate, which makes the blood more alkaline. Bethany's condition improved, but Simone's didn't.

Bethany had the hard task of informing Simone's mum, Sue, that they were all in hospital.

"I was originally told Simone was doing a bit better in the morning, so that was what I told her," Bethany said.

"I didn't realise she had five seizures. I thought it was just one. The communication was difficult.

"If they had told me she had five seizures I would have been a lot more urgent about how I was contacting her mum. Initially it was just a text message."

Watch: Bethany remembers the moment she saw Simone in hospital. Post continues after video.

Sue made an emergency dash to south-east Asia from the UK and arrived as Simone was being prepared for emergency brain surgery. Although the surgery was a success, doctors realised the swelling had progressed.

"They basically said, 'regardless of what we do, she is still going to be in a coma, so there's not really any point in doing more for her. We will just have to wait for her to die naturally,'" Bethany recalled.

Because Laos is a Buddhist country, the staff didn't want to end her life, they wanted to prolong it. So, Sue and Bethany called the embassy to liaise with hospital staff.

"The suggestion was that Sue turn off life support, which is what she did," Bethany said.

Simone passed away half an hour after being taken off life support.

Bethany said she was in "a state of shock" when she got back home and, over Christmas, she was bombarded with memories of her best friend.

"I would sort of get up and then feel dizzy and need to sit down and just things like that, really, and I think that lasted for about two weeks," she said.

"Over Christmas, there was a lot of reminders of what we'd normally be doing. And we had, we actually had events planned, which was supposed to be coming up, but obviously, given that she was no longer with us, those days would come up, and I'd just delete them out of the calendar. It was a horrible time."

Simone's funeral was held in January.

"I wasn't in a fit state to attend a funeral the way that I was, and with that little gap that we had, I was able to get a little bit of rest so that I could successfully do a bit of a tribute for Simone on the day of her funeral," Bethany said.

Processing the grief has been a "slow process".

Bethany and Simone have been friends since childhood. They met when they were four and five. Image: Supplied.

"So the trauma is here and the grief is here," Bethany explained. "For me, it's just trying to process what's happened. And, you know, the death of her, really, and the loss, the personal loss I have from not having my friend anymore … She was my guiding light, in a way. If I had problems, she'd be the first person I would contact. So I'm now having to do a lot of internal work to try and work these problems out for myself."

Bethany said raising awareness of the dangers of methanol poisoning has helped her channel her grief — and honour Simone at the same time.

"I think that she would have achieved so much in her life, so if I can do this, so that other people don't have to go through it, then I think that can only be a good thing," she said.

"They couldn't diagnose methanol poisoning as such, because you'd have to send the results off to the Thai lab and that would take two weeks," she said.

"They also didn't have access to the (methanol poisoning) antidote, fomepizole, as third-world countries don't really stock it because it's expensive. They don't know if they will really need it.'"

According to Doctors without Borders, methanol poisoning is responsible for more than 14,000 deaths globally over the last 30 years, with 71 per cent of outbreaks occurring in Asia.

The easiest remedy is knowing the risks.

That's why Bethany launched a petition earlier this year to raise awareness of the dangers of drinking local spirits, which are more likely to contain methanol. Even small amounts — as little as 1-2 tablespoons — can be fatal or cause severe poisoning in adults.

"Don't gamble on your holiday," Bethany said, adding that it would be best to buy alcohol from Duty Free. "It's a really big problem, and it's totally preventable."

Feature image: Instagram.