Those cute embroidered red silk scent bags seem to be everywhere at this time of year during the Dragon Boat Festival season, or Duanwu. That's because they're not just charming and sweet-smelling, but they also serve a medicinal purpose.
According to traditional Chinese medicine, the pouches of herbs help prevent heat stroke, dispel mosquitoes and refresh the wearer. They are usually worn on cords around the neck.
All the World Expo 2010 volunteers from the Shanghai University of TCM wear these sachets made by their schoolmates and have done so since early this month.
Since ancient times Chinese traditionally have considered this month, or season, a dangerous or unhealthy time. That's when temperatures and humidity rise and there are more insect pests and bacteria causing disease.
Carrying a scent bag around for a few months used to be a must. Today the bags are said to be not only health-giving, but also tokens of good luck, longevity and romance.
These pouches are especially popular in southern China where it is especially hot and humid for a long period.
The herbs inside the bag refresh the mind, improve the appetite, boost immunity and help prevent colds, flu and other respiratory ailments, according to Qian Hai, a professor at the Shanghai University of TCM. They also repel insects.
The little bags commonly contain herbs such as cang shu (Chinese atractylodes), bai zhi (angelica dahurica), flag leaf and xin yi (biond magnolia flower).
Research in aromatherapy shows that such treatments work by stimulating the brain, digestive glands and nasal mucous membrane linked to the immune system.
Thus, the right herbs can stimulate the nerves to refresh the mind, trigger antibody secretion in mucous membranes and improve the appetite.
Scent bags are widely available, but it's possible to DIY. Customers can buy ready-made bags and add specific herb powder as needed, depending on whether they want to prevent colds, refresh the mind or dispel inspects - or all of these and more.
Many people carry bags in their pockets and keep them in their beds and cars. Doctors say the herbs work best if the sachet is within 1 meter of the body.
Professor Qian says women should not wear perfume while carrying a scent bag, lest the fragrance reduce efficacy of the herbs. Pregnant women should not wear backs containing herbs such as ageratum for long periods as they can lead to miscarriages, the professor says.
Fresh scent bags are effective for two or three months, but dampness can shorten this period. Herbs in DIY bags should be changed every 10 days to ensure their effectiveness.