"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.