Is it safe to ingest motor oil?


Motor oil is a liquid lubricant used in internal combustion engines to reduce friction between moving parts. It is made from a petroleum distillate and contains additives that help improve viscosity, corrosion resistance, and engine cleanliness. While motor oil is essential for the proper functioning of engines, it is absolutely not safe for human consumption and ingesting it can lead to severe health consequences.

What is motor oil made of?

Motor oil consists of three main components:

Base oils

Base oils make up 70-90% of motor oil. They are derived from crude oil that has been refined and distilled. Common base oils include:

  • Mineral oils – Made from crude oil. They are the most widely used base oils.
  • Synthetic oils – Made from synthesized hydrocarbons or other raw materials. They perform better than mineral oils.
  • Semi-synthetic oils – A blend of mineral and synthetic oils.
  • Re-refined oils – Produced by re-refining used oil.


Additives make up 10-30% of motor oil. They are chemicals added to the base oil to enhance specific properties. Some common additives include:

  • Detergents – Help keep engine parts clean.
  • Dispersants – Prevent deposit build-up.
  • Antioxidants – Improve oxidation resistance.
  • Antiwear agents – Prevent wear between moving parts.
  • Pour point depressants – Improve flow at low temperatures.
  • Viscosity index improvers – Maintain viscosity at varying temperatures.

Carrier fluid

Some motor oils contain a carrier fluid such as polyalphaolefin to dilute the mixture. This helps improve low-temperature flow.

Dangers of ingesting motor oil

While motor oil is essential for engine performance, it contains many components that can be extremely hazardous if ingested by humans. Some key dangers include:

Chemical pneumonia

Inhaling droplets of motor oil into the lungs can cause lipoid pneumonia, a serious condition caused by an inflammatory reaction to the oil. If aspirated into the lungs, motor oil can result in severe breathing difficulties.

Gastrointestinal problems

Ingesting motor oil can irritate the digestive tract, causing abdominal pain, nausea, vomiting, and diarrhea. It may also lead to ulcers in the esophagus and stomach.

Kidney and liver damage

The hydrocarbon compounds in motor oil are toxic to internal organs like the kidneys and liver. Exposure can lead to kidney or liver dysfunction, and even eventual kidney or liver failure.

Neurological issues

Many of the organic solvents and additives in motor oil can affect the nervous system. Acute exposure may lead to headaches, dizziness, tremors, restlessness, and confusion. Chronic exposure could potentially cause nerve damage.

Carcinogenic compounds

Motor oil contains small amounts of carcinogens like polycyclic aromatic hydrocarbons that are formed during the combustion process. Long-term ingestion of these contaminants increases cancer risk.

Aspiration risk

Accidentally inhaling motor oil into the lungs can cause aspiration pneumonia. This occurs when foreign material like oil gets into the lungs and causes an inflammatory response. It can lead to severe lung damage and respiratory failure.

Documented cases of motor oil poisoning

There are a few documented cases that highlight the toxicity of ingesting motor oil:

Case 1

In 2015, a 35-year-old woman intentionally ingested a mug full of motor oil. Within hours, she developed nausea, vomiting, chest pain and was hospitalized. Despite treatment, her condition deteriorated rapidly leading to aspiration pneumonia, sepsis and multi-organ failure. She eventually died from complications just 48 hours after ingesting the motor oil.

Case 2

In 2018, a 40-year-old man drank a glass of motor oil on a dare. He arrived at the emergency room coughing up blood and oil. Tests showed chemical pneumonia and gastrointestinal bleeding. He developed acute respiratory distress syndrome over the next few days requiring mechanical ventilation. Fortunately, he survived after a long hospital stay.

Case 3

In 2008, a 42-year-old man accidentally ingested motor oil stored in a water bottle. He experienced nausea, vomiting, diarrhea and upper abdominal pain after consumption. Endoscopic evaluation revealed inflamed tissue, mucosal friability and ulceration of the esophagus and stomach. He recovered after receiving symptomatic treatment and being monitored closely during hospitalization.

These cases illustrate just how toxic ingesting even small amounts of motor oil can be. Swift medical intervention is critical for survival.

How does motor oil impact the body?

Motor oil wreaks havoc on the body through several mechanisms:

Pulmonary aspiration

Accidentally inhaling motor oil can set off a dangerous inflammatory response in the lungs. Oil droplets that enter the airway can overwhelm the lungs’ natural clearance mechanisms. As the immune system attacks the foreign oil, fluid buildup, swelling, and damaged lung tissue make it difficult to breathe.

Gastrointestinal injury

If swallowed, the corrosive effects of motor oil can damage the lining of the digestive tract. This can lead to mouth sores, ulcers in the esophagus and stomach, abdominal pain, and bleeding.

Toxic accumulation in organs

The components of motor oil are rapidly absorbed from the gut into the bloodstream. These toxic substances then accumulate in tissues and organs like the brain, liver, and kidneys. The resulting cellular damage can impair vital organ function.

Biochemical disruptions

The additives and hydrocarbon compounds in motor oil can disrupt enzymes, cell membranes, and biochemical pathways throughout the body. For example, they may interfere with energy production, electrolyte balance, and normal nervous system function.

Immune reactions

Motor oil in the bloodstream triggers an immune response. Inflammation flares up as the body tries to attack and clear out the toxic foreign substance. This can further damage tissues and cause respiratory distress or multiple organ failure.

Cancer promotion

Many constituents of motor oil have carcinogenic effects. Long-term exposure to contaminated oil has been linked to increased risk of skin, lung, bladder, and stomach cancers.

How is motor oil poisoning treated?

The main goals of treating motor oil poisoning are to stabilize the patient, prevent further absorption of the toxin, and provide supportive care. Treatment may include:


Patients are monitored for respiratory distress, organ failure, shock, seizures, or other life-threatening conditions. Interventions like oxygen, fluids, medications, or ventilator support may be needed.


Swallowing motor oil requires emergency decontamination. This may involve pumping the stomach to remove remaining oil. Activated charcoal can help absorb toxins in the gastrointestinal tract.


Medications that may be used include:

  • Laxatives – Accelerate removal of oil from the GI tract
  • Antibiotics – Treat or prevent pneumonia and infections
  • Corticosteroids – Relieve inflammation in the lungs
  • Antidotes – Counteract some toxin effects

Supportive care

This includes IV fluids, supplementary oxygen, mechanical ventilation, kidney dialysis, and other interventions to support the functioning of affected organs.

Prevention of aspiration

Patients who have inhaled motor oil may need endotracheal intubation and suctioning to prevent further aspiration. The head of the bed is elevated and swallowing precautions instituted.

Psychological assessment

Intentional motor oil ingestion may indicate underlying psychological issues that need to be addressed. Counseling and psychiatric help may be advised.

Long term consequences

For those who survive motor oil poisoning, long term consequences can include:

  • Respiratory problems from chemical pneumonia or aspiration
  • Kidney or liver impairment
  • Increased cancer risk from carcinogenic compounds
  • Neurological issues like nerve damage or tremors
  • Gastrointestinal complications like strictures or adhesions

Ongoing medical care is typically required after discharge. Patients need monitoring for organ dysfunction and screening for cancers. Psychiatric assessment may also be warranted.

Preventing accidental motor oil poisoning

To avoid accidental ingestion, some key prevention tips include:

  • Always store motor oil securely out of reach of children.
  • Never put motor oil in containers used for food or drinks.
  • Wear gloves and eye protection when handling motor oil.
  • Wash hands thoroughly after handling motor oil.
  • Ensure adequate ventilation when using motor oil.
  • Keep motor oil away from heat, flames, or ignition sources.
  • Dispose of used motor oil properly – never pour it down drains or onto the ground.
  • Seek immediate medical help if motor oil is swallowed or inhaled.

Public health initiatives

To further curb motor oil poisoning, public health strategies could include:

  • Childproof caps on motor oil containers.
  • Warning labels clearly stating toxicity and dangers.
  • Public education on safe handling and storage.
  • Restricting motor oil sales to children.
  • Laws prohibiting careless disposal of used motor oil.
  • Initiatives to increase recycling of used motor oil.
  • Packaging regulations to prevent misuse of containers.


Ingesting motor oil is extremely dangerous and potentially fatal due to the hydrocarbon compounds, additives, and carcinogens it contains. Accidental aspiration or ingestion requires rapid decontamination and medical treatment to prevent respiratory failure, organ damage, and other life-threatening effects. Public awareness and secure product handling are imperative to prevent poisoning, especially in children. While motor oil is vital for engine function, it should always be kept far away from human consumption.

Motor Oil Component Potential Health Effects from Ingestion
Mineral oils Gastrointestinal irritation, aspiration pneumonia
Synthetic oils Nausea, vomiting, chemical pneumonia
Detergents Gastrointestinal ulceration, organ damage
Solvents Headaches, confusion, nerve damage
Antiwear agents Kidney and liver toxicity
Carcinogenic compounds Increased cancer risk

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