A public health crisis as stocks of medicinal plants start to decline

An estimated 80 percent of people in developing countries rely on traditional plant-based medicines. Medicinal plants are also vital for producing many important pharmaceutical drugs around the world. However, unsustainable harvesting of the most popular wild plants is depleting stocks and putting public health at risk.

Research from Center for International Forestry Research, and People and PlantsInternational, examines the linksbetween medicinal plant use and public health. Traditional medicine is animportant part of public health care, especially in countries with a chronicshortage of health professionals and poor access to modern medicines.

Medicinal plants are central to Chinese andTibetan medicine, Ayurvedic and Unanimedicine in South Asia, and many local healing practices in Africa and LatinAmerica. Healers use plants to treat diseases, such as diarrhoea and malaria,as well as psychological disorders, including drug and alcohol addiction. But thegrowing demand for medicinal plants in urban areas is leading to unsustainableharvesting.

The most popular medicinal plants grow intropical forests and mountain areas. Many of these are slow-growing andlong-lived species that only grow in these habitats. As well asover-harvesting, they are threatened by climate change, habitat loss andlogging. Of most concern are the rare species that are the only representativesof their plant family.

The research shows:

• Worldwide, anestimated eight percent of medicinal plants are under threat.
• The loss ofplant diversity and habitats will be worst in tropical ecosystems, which areset to lose between 25,000 and 40,000 plant species by 2050.
• The decline inwild stocks increases the cost of herbal medicines, leading some traders tosubstitute plants or contaminate them with dangerous alternatives.
• In Nigeria, many herbal medicines tested containedheavy metals, while some Asian herbal medicines contained arsenic, lead andmercury, in some cases at toxic levels.
• Herbal medicines can produce an adverse reaction whentaken alongside some pharmaceutical drugs, including oral contraceptives,anti-HIV agents, and drugs for cancer and heart disease.
• Growing certain medicinal plants could provide anincome for smallholders, but it is often too difficult or expensive to grow these plants on a large enough scale to meetcommercial demands.

Policymakers mustensure that the harvesting of wild medicinal plants is sustainable. They shouldfocus on conserving and managing forest and mountain habitats, which oftenrequires local participation if these measures are to be effective. They alsoneed to ensure that herbal medicines meet health and safety standards, fromstorage to processing and distribution. Policy options to achieve this include:

• Use traditionalknowledge from local people, such as healers, to identify and record differentspecies, and monitor and assess the effects of medicinal plants.
• Identify ‘safe’ medicinalplants and find out more about how medicinal plants interact withpharmaceutical drugs.
• Developappropriate certification systems for medicinal plants.
• Build marketingnetworks that connect certified plant producers to partners in the medicinalplants industry.
• Expand programmesfor domesticating wild medicinal plants, based on policy agreements betweencountries where the plants commonly grow.
• Develop fieldgene banks to conserve high-priority species.