Cold viruses are stubborn germs that need both coaxing -- and time -- to get out of your system. So you might need some help while you're feeling under the weather.
And it need not come from the pharmacy or medicine cabinet.
That's where the time-honored tradition of folk medicine comes into play in cultures and countries both here and abroad.
In the United States, when people get sick, they have been spooning up chicken soup for generations. The comforting golden broth, sometimes referred to as "Jewish or liquid penicillin," appears to have some therapeutic benefits, both from its ingredients and its warmth.
And while scientists have done a few studies on the soothing potion, surprisingly, there has not been any clinical research done on the effect of hot drinks on people with cold symptoms.
The December issue of the journal "Rhinology" contained results from a very small trial done in Wales. The researchers looked at a group of 30 students, all of whom had cold and flu symptoms for about a week but had not yet taken any remedies or medication to relieve them.
Half the subjects were given slightly less than half a cup of a hot apple and black currant "fruit cordial" to drink, while a control group was served the same beverage at room temperature. (A fruit cordial is a concentrate that's diluted with water before it's consumed.)
Scientists asked the participants to rate their cold symptoms before the study began and after they first drank the purple-colored liquid, as well as 15 and 30 minutes later. The participants were also asked to breathe into a facemask to check on the air flow through their noses.
The hot drink did not make the nose any clearer as measured objectively by the facemask.
But when the participants rated their symptoms, the data found that it eased coughing, sneezing, sore throat, runny nose, chills and fatigue, while the room temperature beverage helped only with coughing, sneezing and a runny nose.
The take-home message from this research, according to its co-author Ronald Eccles, director of the Common Cold Centre at Cardiff University, which sponsored the study, is that "hot fruit cordial drinks provide immediate and sustained relief from most cold and flu symptoms, especially cough and sore throat."
But the study had limitations. Participants knew the temperature of the juice they were given, so they were not "blinded" to the treatment and their symptom ratings might have been a placebo response to them.
It's also not known whether any other kind of hot liquid could have caused a similar effect besides the specific flavored fruit beverage tested. And, possibly, cold beverages could also do the trick but they were not part of the investigation.
So read on to learn more about black currant juice, one of the fruits used in the recent study, and other sworn-by cold remedies from around the world.
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Perhaps it's the memories of and belief in the healing potential of these folk remedies that make them so powerful to us.
Hot Black Currant Juice
"In Finland, there is a common belief that hot black currant juice is an effective remedy against a cold," said Jukka Siukosaari, the international affairs officer for the Finnish Medical Association. At least, "that's what my grandmother used to recommend," he pointed out. "I suppose the vitamins [in the juice] are believed to be behind the effect."
Purple black in color and an excellent source of vitamin C, black currants were used in the United Kingdom as a food source of vitamin C during World War II, when oranges were hard to come by. In fact, black currants have three to four times the vitamin C content as an orange and are valued for their medicinal benefits. Long a trusted remedy for sore throat, the small berries were called quinsy for a form of tonsillitis they're thought to treat.
Black currants come from trees found mostly in Northern and Central Europe and Asia, which is one reason they remain popular in Europe today. The trees were once widely found in the United States, but when the shrub was found to host and spread a disease that threatened the timber industry, they were banned in the early 1900s. By the mid-1960s the federal ban was lifted in favor of allowing states to make their own growing decisions.
Both the fruit and its juice have a sweet and tart taste. The juice can be homemade or sold commercially as a concentrate in the supermarket, explained Siukosaari. If using the concentrate, you add hot water to it and begin to drink the warm juice three to four times a day when your cold symptoms start to act up.
In many regions of China, the popular remedy for a cold is ginger tea.
"You drink it several times a day when you feel symptoms, especially before going to bed," said Dr. Chun-Su Yuan, director of the Tang Center for Herbal Medicine Research at the University of Chicago.
Ginger is an herb that's believed to be warming and to induce sweating, Yuan said. "The Chinese people believe that sweating can cure a cold."
Ginger tea helps you get over the mild symptoms of a cold, said Bing Yang, who chairs the Chinese herbal medicine department at the New England School of Acupuncture in Newton, Mass.
She explains that ginger tea is consumed mostly during the beginning stages of a cold and is not good for a fever or more severe problems. People often add brown sugar to it, which is believed to warm the stomach.
The spicy-tasting tea is made by cutting small pieces of fresh, peeled ginger root into boiling water. This is steeped for five to 10 minutes and then strained. Some people also add the white part of a scallion, which like ginger, is thought to make you perspire.
China is not the only country where ginger tea is popular. The herb also grows widely in India, where its tea is the traditional home remedy for a cold.
Dr. Arti Prasad grew up in India, did some of her medical training there and is now the founding executive director of the University of New Mexico Center for Life in Albuquerque.
She said she would squeeze or crush ginger to get fresh juice. Then mix a tablespoon of the fresh juice in a tablespoon of honey and lick a little bit of this syrupy blend every few hours throughout the day. "This remedy is good for a cold or a cough," Prasad said.
In Ayurveda (Indian medicine), ginger has both dry and sharp qualities, said Sonia Masocco, an instructor for Ayurvedic herbology at The Ayurvedic Institute in Albuquerque, N.M. The herb's dry qualities help to liquefy a cold, which may help stop a runny nose or watery eyes in its tracks. Ginger's sharpness is said to influence the quickness of its penetrating actions.
According to Masocco, the ratio used to make ginger tea in India is about four tablespoons of freshly cut slices of ginger root to one cup of water. She says the key to using this healing spice is its potency. Too much water will dilute the sharpness and dry aspects of ginger.
The tea is boiled or simmered into a pale yellow liquid that has a pungent taste. A ginger paste can also be applied to the chest or forehead to relieve congestion there.
Growing up in Canada as a member of the Mohawk tribe, Dr. Theresa Maresca learned to turn to the plants in her region for medicine. And if her throat started to feel scratchy, she would take a bite of "bitterroot," which is known among American Indians as a treatment for a sore throat or a cold.
Bitterroot goes by many other names including singer's root (the remedy is used for a hoarse voice), said Maresca, now a family medicine physician and director of the Native American Center for Excellence at the University of Washington School of Medicine in Seattle. "You can even find it sold at health food stores as calamus root or sweet flag."
You take a little chunk of bitterroot or bite off a piece, which tastes quite bitter, as its name suggests. The root is hard, and as it softens up, it becomes spongy so you can suck on it for hours, explained Maresca, who typically carries a small piece of it with her when she travels in case she feels a cold coming on.
Bitterroot might work to soothe an inflamed throat or quiet a cough by increasing the production of saliva. And because it also helps calm the stomach, it's sometimes considered "Indian Tums."
American Indians might also turn to teas to ease their cold symptoms. One traditional brew that Maresca likes to steep is a combination of the herb peppermint and yarrow. A medicinal plant, yarrow is thought to increase circulation and promote sweating to help bring down a fever. She describes the tea as pungent with a distinctive, but pleasant smell.
Besides teas, steaming is another popular cold reliever in the American Indian tradition. Boiling water is placed into a bowl, leaves or needles from a fragrant tree (such as juniper or cedar) are added, then you create a tent over your head with a cloth or towel. Breathing in the scented steam helps to unblock sinuses, break up nasal congestion and promote mucus flow.
There is a plant known as wormwood that we have used for centuries as a cure-all for everything, said Frances Miller, a tribal doctor and Inupiat Eskimo, a group found in the Northern coastal region of Alaska. "It's a plant that my people have known about from way back and its medicinal value is highly respected."
Its nickname is stinkweed, referring to its distinct smell. The reason it's called stinkweed, she explained, is because when you go looking for the plant, you know you've found it when you can pinch the leaf with your fingers, touch them to your nose and it smells exactly like menthol.
The best wormwood is found in the coastal areas of Alaska, where the mixture of the salt air and the region's soil make the plant a stronger medication, said Miller, who is affiliated with the Southcentral Foundation's Traditional Healing Program in Anchorage, Alaska, which offers both traditional healing practices along with Western medicine to Alaska natives.
The plant can either be used "green," meaning freshly picked, or dried. It's placed in a pot and boiled for 20 minutes. You remove it from the heat and allow the avocado green liquid to steep. The tea can be served hot or cold.
At the onset of cold symptoms, you might drink a cup of tea, a couple of times a day. But, Miller warned, you need to have food with the beverage because it's a strong, potent medicine that should be used very cautiously.
Besides using wormwood as a tea, you can also gargle with the liquid. Or you can put it in a nasal spray bottle to clear the sinuses and allow the nasal passageways to drain, said Miller.
Pronounced oo-hah-LOW-wah, this native Hawaiian plant is well-known for its medicinal use among traditional healers. The plant looks like a weed, but it's the juice from the inner bark that's thought to be most beneficial for cold symptoms.
According to "Native Hawaiian Medicine," a textbook translated by Malcolm Chun, the bark of the root is good medicine for a sore throat, tonsillitis and chest pain when breathing.
The bitter root from the inner bark might be chewed to release the juice inside the plant. Swallowing this juice as it mixes with the saliva in your mouth could help soothe a sore throat.
The root bark can also be boiled into a reddish-colored tea that's drunk for sore throats as well as for bronchial and bacterial infections.
Dane Silva is a native Hawaiian healer on the Big Island. He described some of the healing methods he might use for a cold: When someone has a cold, the family talks with each other, and we call this concept "ohana." A tradition of the ohana when caring for someone with a respiratory infection may include giving indigenous herbal medicines and massage, accompanied by prayers for spiritual intercession, guidance and protection.
"An herbal tea of uhaloa may be recommended to reduce the intensity of the immune response to the infection. Other herbal beverages made with turmeric [also known as 'olena'] may reduce the inflammatory symptoms," Silva said.
A hot or warmed stone may be placed on the body to regress a cold's symptoms.
A dilute solution of salt water with lemon juice is used as a gargle to cleanse the mucus in the respiratory system. Daily baths in salt water may be advised.
"Sun, salt and water are essential components of traditional Hawaiian medicine," said Silva.
And when you have a cold, the idea of jetting off to a place with sunshine, warm weather, and salt water might just what you'd want the doctor to order.
Hot Lemon Drink
"In New Zealand, when people have a cold, they often make a lemon and honey drink. This is believed to soothe the throat," said Shani Naylor, the communications manager for the New Zealand Medical Association.
This tried-and-true remedy has been passed down through the generations rather than being the treatment of choice from physicians, she pointed out.
As would be expected, the hot beverage is made by combining boiling water, juice from a lemon and honey to taste.
It could be manuka honey, a type that's native to New Zealand and thought to have additional germ-killing and healing properties, but it's not the only option, said Naylor. "Since this remedy gets passed down from families, there's no one correct way of making it."
The residents of this island country might drink it several times a day to relieve cold symptoms.
The lemon adds a bit of immune-enhancing vitamin C and may even help cut down the production of mucus. Besides adding sweetness, honey can coat an irritated throat and ease its raw and inflamed mucous membranes, which can release secretions or become dry. (It's no surprise that lemon-honey is a popular flavor of throat lozenges.)
Sipped slowly and frequently, this hot mixture can be balm to your throat to temporarily ease its pain. And its healing ingredients and warmth might also help break up congestion.
Ginger repeatedly turns up in international remedies.
In the case of South Africa, it comes in the form of ginger ale -- combined with honey and lemon, one of the most commonly used combinations for a cold, said Adri van Eeden, corporate communications manager for the South African Medical Association.
It's made by combining one or two teaspoons of honey and lemon juice with or without a few drops of eucalyptus oil. About one cup of ginger ale is added to this mixture, which is then heated, and sipped slowly like a tea.
It's both the healing powers of the ingredients and the soothing warmth of this golden-colored beverage that has made this folk remedy endure from generation to generation in South Africa. The drink is often used by adults along with some aspirin.
Ginger ale is a home remedy frequently used to ease an upset stomach, which may accompany a cold. Lemon might also tame mucus production and honey could relieve a sore throat. Eucalyptus is a fragrant medicinal oil with a strong menthol-like smell, and its vapors are thought to help reduce nasal congestion and coughing.
Some people in South Africa might also use a bitter medicinal herb called perdepis, which loosely translated means horse urine, a reference to the strong smell of its leaves. The herb, whose botanical name is Clausena anisata and may be called Horsewood, is used as a remedy for cold and flu.
Perdepis root is boiled in water and then strained. A couple of cups of the tea are drunk about twice a day, with or without the ginger ale combination previously described.
Humble and hardy, the turnip has a reputation as a filling and nourishing peasant food. But in the highlands of Bolivia and other parts of South America, people use this root vegetable for healing as well.
Clare Sammells, an anthropology instructor at the University of Chicago, described a local remedy for sore throat made by cutting a hole in the center of a turnip and filling it with sugar. The moisture from the turnip is combined with the sugar into a thick syrup that is drunk.
"It's very viscous and sweet," Sammells said. "It coats your throat."
Though it may not last long, the turnip syrup can form a thin layer over the mucous membrane of the throat, soothing the area, said Dr. William Schaffner, chair of the Department of Preventative Medicine at Vanderbilt Medical School. The protective layer can give the body a chance to heal itself.
"It's a reasonable notion, and just for a few minutes," Schaffner said. "Maybe not to help cure [sore throat] but to give symptomatic relief."
Turnips are high in vitamin C, an important nutrient that helps boost the immune system, which may leech into the syrup. And sugar has antiseptic properties, acting as a germicide to destroy microbes and reduce the possibility of infection.
Cold & Flu season is here! Visit the ABCNews.com OnCall+ Cold & Flu Center to get all your questions answered about these nasty viruses.
Radha Chitale contributed to this report.
Uhaloa Photo Courtesy: Gerald D. Carr, Oregon State University
Cold & Flu season is here! Visit the ABCNews.com OnCall+ Cold & Flu Center to get all your questions answered about these nasty viruses.