With Typhoon Haiyan affecting millions of people in the Philippines city of Tacloban, inflatable field hospitals have proved to be of immense help for the huge international relief effort in the region.
Medecins Sans Frontieres (Doctors Without Borders) have five of the large white tents that they have brought with them from France.
By Thursday afternoon three of them had been erected.
They will give the organisation the capacity to do both in-patient and out-patient consultations, emergency treatment and surgery in a sterile environment, said MSF logistician Damien Moloney.
"It's a pretty big operation," Moloney told AFP in Tacloban on Leyte island. "We're here to give support to the local health structure. We want to help them get back on their feet."
MSF has been working in various parts of the typhoon disaster zone for around a week.
The group's emergency coordinator Natasha Reyes said some of the most serious cases were in Guiuan on Samar island where the storm made landfall, where 600 people came for treatment on their first day of operation.
Among them were some who were injured as a direct result of the 315 kilometre (195 mile) per hour winds.
"We've seen.... people needing minor surgery - procedures needing local anaesthesia for suturing, cleaning of infected wounds and the routine setting of broken bones," she said.
"The team saw some very nasty head wounds. Some had previously been stitched up but had since become infected, and the clinic had to start again and clean the wound."
In other parts of the disaster zone, medics have been dealing with puncture wounds from people stepping on nails as they scramble over the debris, who needed treatment for tetanus.
Reyes said some patients came to them as indirect victims of the storm, including an older man with a serious lung condition.
"He wasn't doing well," she said. "He had lost his inhaler, which is distressing and dangerous in his condition. For people with chronic diseases like that, it's particularly hard."
A lack of clean drinking water has given rise to gastrointestinal infections and diarrhoea, especially among children.
"All of our medical teams are on the lookout for the very dangerous diseases that are endemic in the area - typhoid, schistosomiasis, cholera and leptospirosis," said Reyes.
"The worry is that the conditions people are living in as a result of the disaster might trigger an outbreak."
Typhoon Haiyan, which smashed through the central Philippines on November 8, was one of the most powerful storms ever recorded on land.
Its winds whipped up a storm surge that flooded a large stretch of coastline, destroying buildings and infrastructure.
Around 5,500 people are dead or missing after the storm, which affected more than 13 million people, of whom 4.4 million are now homeless.