All You Need to Know About Methanol Poisoning

Methanol poisoning is intoxication with methyl alcohol (methanol), the metabolic products of which have a harmful effect on the human organism. Depending on body weight and general condition, even less than 30 ml can be lethal.

What is methanol poisoning?

Excessive exposure of the human organism to the toxic methyl alcohol (methanol intoxication) is referred to as methanol poisoning. In general, a distinction is made between acute and chronic methanol poisoning. See AbbreviationFinder for abbreviations related to Methanol Poisoning.

Acute intoxication with methanol is characterized by the single ingestion of a large amount of methanol. If the alcohol is absorbed into the gastrointestinal tract after about 12 to 24 hours, nausea, vomiting, headaches, blurred vision and dizziness manifest themselves. In more severe cases, convulsive convulsions and impaired consciousness can be observed.

Due to the paralyzing effect on the circulatory and respiratory centers, acute methanol poisoning can lead to death. In chronic methanol poisoning, on the other hand, small amounts of methanol are inhaled or absorbed through the skin, leading to visual disturbances and damage to the visual and auditory nerves when exposed over a longer period of time. Loss of appetite, abdominal pain, recurrent irritation of the mucous membranes of the eyes and respiratory tract are other characteristic symptoms of chronic methanol poisoning.


In the case of methanol poisoning, after ingestion (absorption) in the liver, the methanol is converted by the enzymes alcohol dehydrogenase and aldehyde dehydrogenase into its harmful metabolites (metabolic products) formic acid and formaldehyde.

The metabolites are only slowly eliminated or excreted renally (via the kidneys ), so that these two toxic substances are accumulated in the body. While formic acid causes metabolic acidosis with metabolic imbalance, formaldehyde has a direct damaging effect on the adjacent organs.

Poisoning with methanol is mainly caused by the consumption of inferior or improperly distilled spirits, which can contain higher amounts of methanol. In addition, methanol is used in the commercial sector as a solvent for varnishes, adhesives and paints and in the pharmaceutical, chemical and cosmetics industries, which can cause chronic methanol poisoning if inhaled or absorbed through the skin over a long period of time.

Symptoms, Ailments & Signs

Methanol poisoning manifests itself through blurred vision, nausea and vomiting, severe headaches and dizziness. Disorders of consciousness can also occur as a result of acidification. The highly acidic urine has an unusual odor and often takes on a strong yellow coloration. In addition, methanol poisoning can impair hearing.

Those affected are then no longer able to perceive deep tones correctly, and later the high tones are no longer perceived either. Often the liver is also involved and there are signs of jaundice, i.e. yellow skin, paleness and a strong feeling of being unwell. Externally, symptoms such as acidosis are noticeable through a blue discoloration of the lips and pale skin. Strong bad breath and accelerated breathing are also typical.

Long-term methanol poisoning causes vision problems, hearing problems, atherosclerosis, arthritis, osteoporosis, heart failure, and immune system disorders. The chronic form of the disease develops over the course of months or years of repeated consumption of inferior spirits or other products containing methanol. Acute methanol poisoning occurs within hours of drinking alcohol and paralyzes the cardiovascular system and breathing. If left untreated, the acute form can lead to the death of the patient.

Diagnosis & History

In many cases, methanol poisoning can be diagnosed on the basis of the clinical symptoms and information about possible methanol exposure (working with solvents, consumption of inferior spirits) obtained from the medical history.

In addition, an enlarged liver, oliguria or anuria, in severe cases uremia with residual nitrogen and an increase in blood pressure can be detected in acute methanol poisoning. In addition, the urine is acidic and there is a very high concentration of calcium oxalate crystals with a very low number of erythrocytes and leukocytes. Metabolic acidosis can be diagnosed as part of a blood gas analysis (including reduced carbon dioxide partial pressure).

In the case of chronic methanol poisoning, the methanol can be detected in the urine and blood. In addition, an increased formic acid concentration in the urine can usually be detected. The course and prognosis of methanol poisoning correlate with the time of diagnosis and the start of therapy. The later intoxication with methanol is detected, the more likely irreversible impairments are. Left untreated, methanol poisoning is almost always fatal. In addition, long-term effects, in particular loss of vision, can be observed in the case of methanol poisoning.


In general, methanol poisoning has a very negative effect on the patient’s health and can even lead to death in the worst case. However, this only occurs when large amounts of methanol have been introduced into the body. However, even small amounts can cause severe damage, which can primarily affect the internal organs and the brain.

The damage is usually irreversible. As a result of methanol poisoning, those affected suffer from severe visual disturbances and, in many cases, blurred vision. There is also vomiting and severe nausea. Patients also complain of dizziness and headaches, and also suffer from impaired consciousness. The thoughts and actions of those affected are also significantly restricted by methanol poisoning.

As a rule, methanol poisoning must be treated acutely by an emergency doctor or in a hospital. Consequential damage can be avoided with gastric lavage. Complications usually only occur with higher amounts, which can lead to damage to the internal organs. However, the exact course of the disease depends very much on the amount of methanol taken.

When should you go to the doctor?

People who experience sudden symptoms such as vomiting, nausea, dizziness or headaches should consult a doctor. If the usual vision is impaired or if the general risk of accidents increases, a medical examination is required. If the symptoms increase in scope or intensity, a doctor must be consulted. Disorders of consciousness are signs of an existing irregularity that needs to be investigated and treated. If you lose consciousness, call an ambulance. Before the arrival of the emergency doctor, first aid measures must be taken to ensure that the person concerned does not die prematurely.

A pale or yellowish complexion, cold limbs or discolored lips are further indications of a health problem. Blue discoloration of the lips is a hallmark of methanol poisoning and should be treated as soon as possible. Hearing loss is a cause for concern. If the affected person can no longer hear deep sounds in particular, it is advisable to see a doctor.

If you feel generally unwell or have an unusual bad breath, you should seek medical advice on the symptoms. If the person concerned suffers from a weakened immune system, a decrease in internal strength or from insomnia, a doctor is needed. If irregularities in the heart rhythm occur, further medical tests should be carried out immediately to clarify the cause.

Treatment & Therapy

Since methanol is metabolized only slowly, gastric lavage is usually carried out first in the event of methanol poisoning. Another therapeutic measure is the inhibition of methanol oxidation by orally applied or infused ethanol or fomepizole.

Both substances have a much higher affinity for aldehyde dehydrogenase and alcohol dehydrogenase, so that the metabolism of methanol in the liver can be effectively suppressed through to renal elimination. In addition, alkalizing substances such as sodium hydrogen carbonate and trometamol are administered in parallel to compensate for the metabolic acidosis (pH value in the arterial blood is acidic or below 7.35). As a result of the resulting normalized extra- and intracellular pH value, the degradation of formic acid is accelerated (increased degree of dissociation), which can reduce the toxic effect.

In addition, the damaging effect of formic acid can be accelerated by high doses of folic acid, which promotes the oxidation of the substance to carbon dioxide. In severe cases of methanol poisoning (more than 100 ml ingestion volume) or in the presence of renal insufficiency, hemodialysis (kidney replacement procedure) is required to quickly eliminate the methanol and its metabolites.

In the case of chronic methanol poisoning, stopping exposure (avoiding all sources of methanol) and changing your diet (food rich in vitamins and protein, increased fluid intake) are generally recommended. In addition, the organ damage caused by methanol poisoning should be treated.

Outlook & Forecast

The further development of health in the case of methanol poisoning depends on the amount of high-proof alcohol consumed, the weight of the person concerned and their general condition. The higher the absorbed level of methyl alcohol, the more unfavorable the further course. Under optimal conditions, the symptoms can be alleviated within a few hours.

In most cases, symptoms are relieved within one to two days. The prerequisite for this is that the person concerned is in good health and has a weight within the normal range of the BMI. In addition, there should always be a good and balanced lifestyle in order to achieve lasting relief from the symptoms.

However, if you consume a large amount of methyl alcohol, there is always a danger to life. In addition, irreparable damage to the internal organs can occur and cause lifelong impairments. If you are in poor health and have previous illnesses, the further course is usually unfavorable. If an alcohol disorder is already present, consequential damage can hardly be ruled out.

Normally, the lower the patient’s weight, the greater the further complications and long-term health impairments. In acute cases, only an ambulance and intensive care can save the life of the person concerned. In these situations, brain damage is to be expected. These worsen the general quality of life.


Methanol poisoning can be prevented by not drinking high-proof spirits of unknown origin or of inferior quality. In occupational activities that involve exposure to methanol, the appropriate protective measures (including protective gloves, clothing, eye and face protection, well-ventilated rooms) should be taken to avoid methanol poisoning.


Since methanol poisoning is a serious type of poisoning, adequate follow-up care is extremely important. In order to rebuild the damaged intestinal flora, patients can, for example, take a course of treatment with lactic acid bacteria. It is generally advisable to invigorate the stomach for a while after the acute phase with a gentle diet.

Since the immune system is weakened by food poisoning, the susceptibility to germs is increased. The focus should therefore be on getting used to food carefully and on medical observation by the attending physician. Those affected are responsible for keeping themselves away from substances containing menthanol.

You can do that yourself

In the case of mild methanol poisoning, the person affected should drink sufficient quantities of non-carbonated and natural mineral water. The intake of water reduces the percentage of methanol in the body, as it mixes with water. The total amount of fluids also causes it to be excreted more quickly. In some cases, this improves physical well-being.

Rest should be maintained and overexertion should be avoided. In order to keep the risk of injury as low as possible, it is helpful if the person concerned sits down and pays attention to the changes in the organism. If his condition gradually improves, there is a good chance that he will be symptom-free in a while. If the symptoms increase, a doctor should be called, since the possibilities for self-help have been exhausted.

In case of severe poisoning, only medical treatment will help. There is a possibility that organs are damaged and permanent damage can result. The longer a consultation with a doctor is avoided, the stronger the symptoms. During ongoing treatment, individual options for self-help can be worked out in cooperation with the doctor. These focus on optimizing a healthy lifestyle. This includes a balanced diet rich in vitamins and sufficient exercise. Avoid toxins such as alcohol or nicotine.