Scientists in India believe they may have found a cheap and effective cure for arsenic poisoning.
Contaminated water is a major cause of arsenic poisoning
Tests on mice suggest the homeopathic remedy arsenicum album can reduce the liver damage caused by the poison.
The remedy which costs just a few pounds is sometimes used by people suffering from anxiety or depression.
But researchers at the University of Kalyani say their tests show it may also have a role in treating people who have been exposed to arsenic.
Millions of people around the world are at risk of arsenic poisoning through contaminated water or food.
Arsenic occurs naturally in the environment to varying degrees. Levels are particularly high in West Bengal and Bangladesh where as many as 40m people are believed to be risk.
The contamination is thought to have occurred naturally, as a result of arsenic being released from rocks into underground water supplies.
Arsenic can kill humans quickly if consumed in large amounts, although small, long-term exposure can lead to a much slower death or other illness.
Studies have linked prolonged exposure to arsenic with cancer, diabetes, thickening of the skin, liver disease and problems with the digestive system.
It has also been associated with nervous system disorders - feeling tingling or losing sensation in the limbs - and hearing difficulties.
Professor Khuda-Bukhsh and colleagues tested the homeopathic remedy on mice which had been exposed to arsenic.
They found that a drop of Arsenicum Album three times a day reduced arsenic levels in the mice dramatically in just 72 hours.
"The potentised homeopathic drug Arsenicum Album not only has the ability to help remove arsenic from the body, but these drugs in microdoses appear to have the ability to detoxify the ill-effects produced by arsenic in mice," said Professor Khuda-Bukhsh.
The researchers said their findings indicated that the remedy should now be tested on humans who are most at risk of arsenic poisoning.
"An early clinical trial may be worth pursuing to verify the efficacy of the homeopathic drug on human volunteers living in arsenic infested areas."
Kate Chatfield, a homeopath and a lecturer in homeopathy at Lancashire University, said she was not surprised by the findings.
"I am not at all surprised. Homeopathy works on the principle that like treats like.
"If we give the body a tiny amount of something, it can stimulate the body to overcome symptoms that are actually caused in different circumstances by larger doses."
She backed the call for large scale clinical trials in humans.
"We need these kind of trials to back the anecdotal evidence that the remedy works."
The study is published in BMC Complementary and Alternative Medicine.