A feverish patient, he says, is put into a hot bath to push the fever even higher. After the bath, the patient is wrapped in an absorbent bark that retains the heat while soaking up the sweat the treatment induces. Newspaper works as well, although it leaves patients ink-stained, he says.
The theory behind the treatment is that fever is the body's way to fight a virus, so anything that raises the temperature helps, Castro says, adding that it's important to change the bark or newspaper wrapping regularly so the patient doesn't get chilled.
And how does the treatment feel? "It feels terrible!" he says. "It makes you delirious and it is a bit painful. But after you have gone through the experience, it makes you feel a whole lot better. It has pushed the fever to the limit and when something is pushed to the limit, it swings back to normal."
Like the Asian rubbing therapy, the Chipcha sweat is a heat-based treatment that has met with concern among American medical practitioners, who say conventional Western care seeks to reduce fevers, especially those at levels high enough to trigger convulsions.
But Susan Scrimshaw, a medical anthropologist who teaches at UCLA's School of Public Health, says many cultures share the notion of healing heat.
In Europe, for example, keeping the sick warm and warmly nourished are practices rooted in the humeral theories of ancient Greece. These practices, she adds, have been reinforced over centuries of use. This may help explain why those of European ancestry turn to hot teas, and, of course, to chicken soup (no list of cold treatments would be complete without it) as cold remedies.
Remarkably, the same concepts have existed since ancient times in South America and China, providing a common philosophical basis for treatment, Scrimshaw says, adding: "The lore in Latin America holds that you can catch a cold by going out barefoot, say, as I do every morning to pick up my newspaper. And cold things will make it worse, so you drink warm liquids, eat warm foods."
She grew up in Guatemala, the daughter of an American doctor who, she says, ignored colds because he couldn't do anything about them. So she borrowed a bit from the Guatemalans, drinking mint tea with honey, and a bit from her grandmother, a New Englander who swore by slippery elm cough drops.
Slippery elm cough drops? The hard candies were widely used in New England, perhaps because the manufacturer was based in Lincoln, Mass. But Scrimshaw believes the custom originated with area Indian tribes who passed on to the Colonists the medicinal uses of slippery elm bark.
Slippery elm lozenges since have slipped into national distribution and can be found in many California health food stores. They also stock: herbal "cough syrups," which are packaged slickly but have as their main ingredient honey, little different from the remedy spooned out by grandmothers; and eucalyptus oil, which Saenz's Vietnamese elders sprinkled in a vat of boiling water to create a pungent, sinus-clearing steam.