At least 48 people had died by Monday after drinking contaminated alcohol which was sold by local traders in Kenya's Machakos district, southeast of Nairobi, medical and police officials said.
Another 84 people had been treated in hospital for suspected methanol poisoning, the medical superintendent of the Machakos district hospital, Simon Mueke, said. Twenty-two of those being treated were in serious condition.
Three people had lost their eye sight, while another five had developed "eye complications", Mueke said. Most of the deaths, he added, had occurred on Friday and Saturday.
Methanol, a highly toxic alcohol commonly used as an industrial solvent, is believed to have been added to a home-distilled gin apparently in an attempt to make it more potent, according to Mueke.
Permanent or partial blindness in methanol-poisoning, he added, results from retinal damage caused by intra-retinal metabolism of methanol and the accumulation of formic acid. Inhibition of normal metabolism in the optic nerve cells due to the presence of methanol could also lead to blindness, he said.
"Death is in most cases the result of liver or kidney failure," Mueke said.
He said doctors were using conventional ethanol, including vodka, to treat the methanol poisoning cases because ordinary alcohol inhibited methanol metabolism in the body and enhanced the elimination of the toxic unmetabolised poisonous compounds.
"We have been using vodka because it displaces methanol from the receptors in the blood," Mueke said. Those who were very sick, he added, were being asked to take sips of vodka.
A police spokesman said they had arrested four people, including a woman bootlegger said to have supplied the killer drink. Some 105 litres of the drink had been seized and samples would be taken to the government chemists for analysis to establish what exactly the alcohol was laced with.
Adulteration of home-made alcoholic drinks with industrial chemicals has become a common problem in Kenya during the past few years.
More than 130 people died in a slum in Nairobi in 2000 after consuming contaminated liqour.
In 1998, the government banned several locally distilled low-priced liquors, but the consumption of "chang'aa" - a popular gin distilled from fermented maize meal or sorghum remained widespread despite frequent police raids on suspected distillers.
Kenya's internal security minister, John Michuki, told reporters the woman who supplied the drink was a "well known peddler who has been arrested on numerous occasions, but the law being an ass, has not been able to convict her".