Tibebu Orcho holds up a packet of seven plastic bags, each filled with a finely ground, dark green leaf, and asks us to inhale its head-clearing scent.
Artemisia annua, or sweet wormwood, has become his main source of income, and a life-saver for his community. Artemisia is an ancient cure for malaria; the Masai in Kenya used a variation of the plant, and the Chinese have long known about its medicinal properties. Now farmers in Ethiopia are discovering its virtues.
Mr Orcho grows artemisia in his idyllic garden, alongside apple trees and rows of cabbages. Once the plant is ready to be harvested, he cuts off the leaves, dries them and crumbles them up. He then fills plastic bags, seals them with a candle and sells them to neighbours to be made into tea. He tells them to pour one litre of boiling water over five grams of dried leaves. If they have no scale, he tells them five grams is the amount that just fits into a plastic 35mm film container.
"I used to buy these leaves, at 5 birr [30 pence] for a dose when my children got malaria," he said. "Then people from the community project (run by Send a Cow) told me I could grow it myself. I was hesitant at first, but I tried and it worked.
"Before, if people couldn't get any medicines when they shivered from malaria, they would just sit in front of the fire and try to keep warm. I am happy I am able to help them now."
Mr Orcho is at the forefront of a new stage of the ongoing battle against the disease. Artemisia, which grows wild in China and Vietnam, is considered one of the most effective treatments against malaria in the world.
Experiments began in China in the 1970s but Mao's government kept it secret for decades. Only recently has the West fully understood its virtues; research shows that artemisia remedies cure 90 per cent of patients in three days.
The new cure for malaria comes just in time. In the past decade, infection has risen sharply, killing three million people worldwide, most of them children under five. Another 300 million people who caught the illness now regularly suffer from high fevers. Sub-Saharan Africa, where millions have no access to reliable health care, bears the brunt: scientists estimate the average number of cases per year in Africa has quadrupled since the 1980s. Scientists call it the silent holocaust.
New strains of the malarial parasite which are resistant to older drugs have spread rapidly. The World Health Organisation (WHO) and international drug agencies now consider artemisia to be the most cost-effective solution. It works by destroying malarial parasites in the bloodstream.
The parasites are resistant to most existing anti-malarial drugs, but artemisia's structure is so different from other anti-malarial drugs that the parasite does not recognise it.
In April, the Global Fund, the WHO, the World Bank, Unicef and the United States Agency for International Development called on malaria-prone countries to phase out older drugs like chloroquine and use multi-drug combinations containing artemisia or its derivatives.
But already there are problems. The rising demand for the drug has led to a worldwide shortage. Prices have quadrupled and the few companies that make the medicine have cut back production. The price of artemisia was about £60 a pound, but as soon as the international agencies made their requests, prices shot up to around £210 a pound.
Novartis, the Swiss pharmaceutical company, now says it can produce only half the 4.5 million courses of the Co-Artem drug it promised to make for the WHO, because its supplier in China has not grown enough of the plant. Drug companies in India have said they are willing to pay any price for the plant. As a result, many countries, including Ethiopia, which were encouraged to adopt artemisia-based drugs, will have their supplies rationed.
All this is happening in tandem with another approach to the problem. In Ethiopia, people working with the British charity Send a Cow began experimenting with artemisia four years ago. They acquired seeds from a European organisation - Action for Natural Medicines - and discovered the plant grows well in the cool, clear air of Ethiopia's southern highlands. Send a Cow covered the initial costs and provided training for farmers to grow, package and sell the medicine in the lowlands, where malaria is a common killer. They are trying to persuade Ethiopia's Ministry of Health to recognise their work and to look at ways of developing the drug, instead of buying it from European pharmaceutical companies.
"It's infuriating to read how Novartis cannot find enough artemisia when our farmers are growing it in their backyards," said Theopholus Tesfaye, an agriculturalist working with Send a Cow Ethiopia.
"The Ethiopian government buys in expensive medicines derived from Artemisia when the crop is growing in its own country. We need to go and persuade them to rethink their policy."
In the meantime, in Chencha, a town consisting of a row of shacks and tiny farms dotted around the mountainside, an artemisia cottage industry is growing fast. Farmers grow rows of the delicate plants in their back gardens, and Send a Cow provides advice on when to harvest the crop and how to process it. They use the money they gain from selling the medicines to buy livestock, apple saplings and clothes for their children.
The people who buy the treatments are grateful, too. Before they had access to a regular supply of artemisia, anyone who caught malaria would have to trek for miles to reach the nearest clinic. Even if a family could afford to pay for it they would not be guaranteed treatment, as the clinics often ran out of medicines.
"The artemisia plant has given this region a whole new industry," said Mr Tesfaye. "We may not have national recognition yet, but at least we can help our immediate community to fight malaria."
In Africa, a cure for malaria could provide the key to development. Economists at Columbia University estimate that countries hit hardest by the most severe form of malaria have economic growth rates 1.3 percentage points lower than those not seriously affected.Artemisia could provide the springboard for development: there are indications that it could be used to treat other diseases, from breast cancer and leukaemia to haemorrhoids.
Most importantly, scientists are also looking at its ability to cure HIV-Aids. Ethiopia is currently one of the most heavily affected countries in the world, with around three million people infected with the HIV virus at the end of 1999. The ability to grow its own anti-malarial and HIV-Aids treatment drugs could revolutionise health care in Ethiopia.
Mr Orcho, who retired from the Ministry of Health three years ago, is one of the linchpins of the system.
He sells each course of seven-day treatments for 5 birr - an affordable amount for most families. Yet he has still managed to earn 3,380 birr [£203] in a year. When he worked for the government, he earned just 1,400 birr a year.