Sri Lanka has been suffering from a growing epidemic of suicide attempts. 

It is fuelled by the ready availability of poison from the fruit of a common roadside plant. 

Michael Eddleston is a British doctor who has spent much of the past ten years in Sri Lanka. 

It is becoming the suicide capital of the world. The poison of choice is the seed of the Yellow Oleander tree. 

The Yellow Oleander is an ornamental plant often used for hedging that grows all over the island. 

It has yellow trumpet-like flowers and a fruit the size of a conker. Inside is a single large seed. One is enough to kill you. 

Although the plant grows in large parts of the tropics, it's only in Sri Lanka that it has become associated with suicide - and only fairly recently, with an incident 25 years ago. 

Two girls in the northern part of the island took the seed and died. 

Publicity 

As a result of the newspaper publicity it entered the public consciousness. 

"The next year," says Michael Eddleston, "there were 23 cases; the year after that 46, then 126, and ever since then it has continued to rise year on year as it spreads across the island. 

"It completely overwhelms the health service. Often young people use it as a way of getting back at people. They get scolded and they take a yellow oleander seed. 

"I remember one girl said her mother wanted her to get up and do the shopping. She said no, her mother scolded her and she took a Yellow Oleander seed. 

"I remember a Muslim girl - her mother said she couldn't watch TV during Ramadan, so she took a seed in front of her mother. 

"We had no ambulance to get her in time and we had no good treatments. She died." 

Family strife 

It's not just young people. In a remote hospital in Pollonaruwa, where Michael Eddleston has done much of his research, I met an old man, a strict Buddhist, recovering from a suicide attempt. 

He had fallen out with his wife, over his habit of feeding the neighbourhood dogs. You care more about those dogs than me, said the wife. 

The man, feeling that his Buddhist principles were under attack, walked out and swallowed a seed from a tree in his garden. 

Luckily, relatives discovered him and got him to Pollonaruwa in time. 

Many of these protest suicide attempts are only semi-serious but up to 10% of them are fatal anyway - a much higher percentage than in the west, where we have good anti-poisoning drugs and facilities. 

Michael Eddleston wanted to do something about that. 

The poison from Yellow Oleander is similar to a drug used in the West to treat heart beat irregularities, digoxin. Digoxin slows down the heart beat. 

Dramatic effect 

An oleander seed is like 100 digoxin tablets in one container, and the effect on the heart is dramatic: it gets slower and slower, and then stops. 

Western doctors have at their disposal an anti-body against digoxin. 

Michael Eddleston thought it might also work against Yellow Oleander, and ran a trial in Sri Lanka to test the theory. 

The drug did indeed work, but no anti-digoxin is currently used in Sri Lanka. Why? Because it's too expensive. To treat one patient could cost in the region of $3000. 

The price is held high because of the American market: most clients are American doctors who have accidentally given their patients too much digoxin and need to get the heart going again. 

For them, it's worth paying almost anything to avoid a law suit. 

So the price of the drug remains high, geared to a market which demands the highest quality, purest drug - a purity that is an unaffordable luxury in Sri Lanka. 

Money pressures 

For much of the last decade, Michael Eddleston has tried to find a local manufacturer in the Indian subcontinent that can make anti-digoxin at a price the Sri Lankan market can afford. 

But, I wondered, will this ever be seen as a priority in a country that has so many calls on its health care budget? 

Isn't there bound to be a lack of willingness to spend money on people who have brought their problems on themselves? 

If so, it's not an attitude I found at Pollonaruwa hospital. Dr Kachana, one of the doctors on the poison ward told me: "I feel very sorry about these innocent people. 

"Most of the time they get oleander with very small, minor reasons. I think we have to do something to reduce the rate of admission to the hospital." 

And she recommends a government campaign to get people to cut down their Yellow Oleander trees. 

It won't be easy. In a village I spoke to a poisoning victim who still had the plant that nearly killed him in his garden. 

Had he thought of cutting it down, I asked. Yes he had, he said. But the plant was still there.