Cooling the body on purpose sounds extreme, but new research suggests it might help shield the brain during a stroke.

Scientists at the Beijing Institute for Brain Disorders in China and other institutions reported that a two-drug combination could clinically induce hypothermia in lab animals and people. In animals, lowering body temperature appeared to slow metabolism and delay the development of brain damage from stroke. In an early trial involving stroke patients, the treatment appeared to be safe and well-tolerated.

The researchers published the findings in Science Translational Medicine and called for larger trials of induced hypothermia to treat stroke and similar conditions.

“Hypothermia and hypometabolism hold promise for helping patients with acute severe disease,” the researchers wrote in their paper.

Scientists have long explored hypothermia as a possible treatment for medical problems because lowering body temperature can slow cellular metabolism. That may prevent or limit destructive processes that some cells go through during conditions such as stroke.

Induced hypothermia is already used at times after cardiac arrest to limit brain damage. But it is generally used only on unconscious patients, because conscious people resist cooling, including by shivering heavily. Physical cooling methods can also be hard for awake people to tolerate for long periods and can cause serious bodily stress.

The researchers said earlier studies showed certain drugs and interventions such as ultrasound could induce hypothermia in mice without requiring freezing temperatures. But it has remained unclear if those methods can safely do the same in large primates such as humans, or if that hypothermia could then help treat stroke.

For the new experiments, the team used a combination of chlorpromazine, a first-generation antipsychotic, and promethazine, a long-used histamine. They first tested the drugs in mice and rhesus macaques with stroke. In both animals, the treatment appeared to protect the brain and reduce the risk of neurological complications.

The researchers then used the drugs in a phase 1, placebo-controlled trial involving 32 patients with acute ischemic stroke, the most common type of stroke and one caused by a blood vessel blockage in the brain. Patients received either a placebo or one of four different doses of the drug combination.

Phase 1 trials are mainly designed to test safety, and all four doses appeared to be safe and well-tolerated. The researchers also found biomarkers of reduced metabolism in all treatment groups, though only the highest dose appeared to reliably lower body temperature.

“Evidence spanning rodents, rhesus monkeys, and patients with stroke demonstrates the translational potential of C+P treatment,” the researchers wrote. “This study may serve as a basis for further phase 2 studies.”

Read more from Gizmodo.