Winter is coming, and the days are getting shorter. This is the time when you easily catch a cold and the consequence is often an annoying cough. But don’t worry, there are lots of different cough medicines available in pharmacies. However, did you know that one tiny plant growing in the large marshlands around Oulu is an ingredient of many cough medicines?

Sundew is a small carnivorous plant growing in mires and marshes all over the world. The historical use of sundew is similar to its use in modern herbal medicine. Tea made of the dried plant matter was recommended in Europe by herbalists for dry coughs, bronchitis and whooping cough. The herb is also said to have antimicrobial characteristics. The active constituents of sundew are naphthaquinones which can give relief from coughing spasms. In many European countries sundew is endangered due to the disappearing of its growing sites, the mires. As a consequence of intensive peat production and drying of mires for gaining productive agricultural land, only small patches of former large marshlands have remained. However, here in the northern parts of Fennoscandia, there are still large mires where the sundew is not endangered. 
 
In 1972, a Swiss factory became interested in buying round-leaved sundew (Drosera rotundifolia) from Finland for medicine production. They were very satisfied with the quality of a plant sample sent to them, and a sundew export business was started. In the best years of the business, 2300 kg of dried sundew was exported to Switzerland, Germany, Belgium and France. Nowadays, plant material is exported only to Switzerland and Germany. The amount of plant material for export is smaller now because of cheaper concurrence from Eastern Europe. However, the good quality of the plants helps to keep the business going.

Sundew picking and nature protection
In Finland most of the sundew is collected in the northern province of Pohjois-Pohjanmaa by individuals.  “It’s easiest for children to pick the tiny plants with their small hands. Often whole families go on trips onto mires in July and August to pick sundew. At the moment, there are about 150 families in the Oulu area who pick sundew regularly,” tells Katja Kolehmainen from the 4-H Society of Oulu. With sundew, the picking season is 3-4 weeks in July and August. After picking, sundew is brought to the 4-H Society, which pays around 30 euros per kilo for the plant material. However, the plants are small so that it takes time and effort to fill the bucket. The sundew is dried, packed and exported as raw material.
 
Thus far, only wild plants are used for medical purposes. According to the WWF, most of the plant material comes from Madagascar, Finland, France and Spain. Because of the small size of the plants, one kilogram can contain several thousands of individual plants. To fulfil the yearly marked requirements of several tons of plant material, up to 200 million plants have to be picked each year. That causes severe problems especially in Madagascar, where picking is far from being sustainable. Furthermore, the Madagascarian sundew species Drosera madagascariensis does not contain as high amounts of the active constituent as the northern European round-leaved sundew, and therefore larger amounts of the drug have to be used for the production of cough medicine. In many European countries sundew is already an endangered species and should not be picked at all.
 
In the large marshlands of northern Finland, sundew is not endangered. Furthermore, there are strict measures for keeping the production of the natural cough drug sustainable. “Pickers have to attend a seminar in which we teach them nature-friendly sundew picking. Enough sundews have to be left over to ensure the plants reproduction from seed during the following spring. We won’t buy plant material from anyone who has not attended the seminar” explains Kolehmainen. Picking plants from nature protection areas is forbidden. The 4-H Society works in co-operation with the university and MTT Agrifood Research Finland for testing the sustainability of sundew-picking and to supervise the quality of the raw material.

Research on sundew
At the University of Oulu there an ongoing research project ongoing to study the concentration of naphthaquinones, the cough medicine, in sundew plants from different regions in Finland. “Until now, it is not at all clear in which part of the plant the substance is synthesized. We are also interested in which genes take part in the production and why the concentration of the naphthaquinones varies between years and single mires but not between Northern and Southern Finland,” explains prof. Anja Hohtola, a member of the research group.
Maybe sometime in the future it will be possible to grow sundew with a high content of the cough medicine, like herbs or vegetables. Consequently there would be no need for unsustainable picking of wild sundew anymore.
 
Other interesting facts about the sundew
Sundew is not a “normal” plant but a carnivorous plant which traps and eats insects. The sundew's leaves are covered with many sticky hairs looking like dew or nectar.  When an insect lands on these hairs to drink the nectar, it gets stuck.  As it struggles to escape, it gets covered with digestive enzymes which eventually help to break down the insect’s body so that the plant can absorb nutrients it can't get from the nutrient-poor marshland soil in which it grows. In Finland, there are three species of sundew. Other carnivorous plants growing here are bladderwort and butterwort.