Experts say some users of illicit alcohol have developed long-term health problems, including loss of sight, kidney damage, memory loss and reduced ability to work.
They warn that the impact also extends to families, with some users unable to care for their children or maintain their jobs.
Illicit alcohol refers to any alcoholic beverage that is produced, smuggled, distributed or sold outside a country's legal and regulated systems.
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These include homemade or adulterated drinks prepared under unsafe conditions, where some producers add harmful substances such as methanol, solvents, crushed bricks, soap or other chemicals.
"These substances gradually affect the brain, blood circulation, kidney function and the heart. Some young people are now on dialysis because of the damage caused," health minister Dr Sabin Nsanzimana said.
Consumption of illicit alcohol containing methanol can lead to severe health complications, including vision loss, coma and death, according to Innocent Habimana, an eye health and public health expert at Rwanda International Institute of Ophthalmology (RIIO).
How methanol affects the body
Habimana explained that approved alcoholic beverages contain ethanol, which can be safe for human consumption when taken moderately, unlike methanol, a highly toxic substance that can cause severe health complications, including coma and death.
"Methanol and ethanol may look similar because they are both colourless, flammable liquids with almost similar smells, but their chemical composition makes them different. Methanol has one carbon atom, while ethanol has two, and that small difference changes how the body processes them.
"Methanol is commonly found in industrial products such as cleaning fluids, detergents and antifreeze, and it is not meant for human consumption," Habimana said.
Habimana explained that methanol becomes dangerous when it enters the body because it is converted into formaldehyde, a toxic chemical that can damage the brain, affect the nervous system and harm vital organs such as the stomach, liver and kidneys.
He added that the process can also cause a buildup of acids in the bloodstream, known as metabolic acidosis, which affects the visual pathways and can lead to vision loss.
"When that metabolic acidosis accumulates in the bloodstream, it severely affects the central nervous system. People who consume methanol can lose consciousness," he said.
The buildup can also affect the retina, which is responsible for vision, causing optic atrophy and vision loss.
"The blindness can occur between 24 and 48 hours after consuming methanol, but it can also happen within hours. It is dangerous because it causes acute loss of vision," Habimana said.
Risks of exposure
He explained that the severity of methanol poisoning depends on the amount consumed, with 10 millilitres capable of causing blindness and 30 millilitres potentially leading to death.
Before severe complications develop, people exposed to methanol may experience symptoms such as nausea, vomiting and abdominal pain. Habimana said that as toxic substances build up in the body, they can begin affecting the brain, vision and other organs.
Excessive alcohol consumption can lead to long-term health effects, including alcohol dependence, which affects the brain and a person's mental health.
The health expert added that people who consume large amounts of spirits or drink traditional alcoholic beverages prepared under unsafe conditions face a higher risk of methanol exposure.
Those with existing health conditions may suffer more severe effects because their bodies are less able to cope with the harm caused by toxic substances.
"People with conditions such as cardiac problems may experience more severe effects when those conditions are combined with high alcohol consumption, especially methanol exposure. However, methanol can affect anyone regardless of their age or health status because the body cannot handle it effectively."
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He explained that older people, mainly those above 40 years, may face a higher risk because their bodies may not process toxic substances as effectively. People exposed to methanol can receive treatment if they seek medical attention early.
"People should be very cautious about the alcoholic drinks they consume, especially cocktails, spirits and homemade beverages. They should only take approved and authorised products. Homemade alcoholic drinks are a concern because their preparation is not always controlled, and it can be difficult to know the actual level of alcohol they contain."
From January to July, more than 50 people died after consuming illicit alcohol, about 100 lost their sight, and more than 500 sought medical treatment due to related complications, according to the minister.
Rwanda prohibits the production, sale, transport, and consumption of illicit alcoholic beverages, including products made outside approved standards or adulterated with harmful substances such as methanol.
