Benzoic Acid: Health Effects And All You Need To Know



So What Is Benzoic Acid?

Benzoic acid, (C7H6O2 or C6H5COOH), is a colorless crystalline solid and a simple aromatic carboxylic acid that naturally occurs in plants and animals.

In large amounts, they have been found in most berries- cranberries, cinnamon, plums, currants, cloves- and ripe fruits.

When produced in the lab, Benzoic acid is a white, crystalline powder with a faint smell. It is commercially produced by partial oxidation of toluene with oxygen; using cobalt or manganesenaphthenates as catalysts.

Industrially they are used as plasticizers and anti-microbial agents in the preservation of processed foods and other consumer products. They are important in the synthesis of organic substances.

Benzoic acid was discovered in the sixteenth century. It is a cheap and readily available substance. Benzoic acid makes high yields especially when inorganic solvents are used in its purification by recrystallization. The use of organic solvents makes the experiment unsafe.

By the beginning of the 20th century, it was used as an expectorant, analgesic, and antiseptic. It is used in the making of anti-fungal ointments used for treating skin diseases such as tinea, ringworm, and athlete’s foot.

Health Effects Of Benzoic Acid

Benzoic Acid

Salts of Benzoic acid is most commonly used by the food and beverage industries as preservatives. It helps to maintain quality, taste amongst other purposes.

The anti-microbial compound is used in the making of such products as insect repellents, cosmetics, mouthwash, perfumes, shampoos and hair dyes.

Benzoic acid is used to maintain the PH level of personal care products. It can be found also in some medications.

Relatively, Benzoic acid is non-toxic and is excreted from the body in form of Hippuric acid. 75% to 100% of the consumed dose is excreted within 6 hours; and the rest excreted within 2 to 3 days.

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Though not lethal per say, improper handling, excessive amounts (which is rare) and high exposure of benzoic acid can lead to injuries and health risks.

Studies into the health effects of the compound on rats, cats, rabbits and mammals, gave varied results. The degrees of toxicity and reactions varied from the different experiment species.

In rats, the toxicity was very low. Symptoms like diarrhea, weakness of the muscles- leading to hypoactivity and emaciation. Inhaling the acid did not kill the rats but increased tear flow and inactivity.

When exposed to cats the toxicity was considered extreme as a result of degenerative changes in liver, kidneys and lung. Generally, symptoms of aggression, skin sensitivity and collapse at high doses (of 1%) were noticed.



Benzoic acid on rabbits showed virtually no sign of intoxication. There was no sign of skin sensitizing on the animals.

When administered to the human skin, a slight irritation was observed. Benzoic acid regardless, was found to be irritating to the eye.

The study found that when administered orally, on the skin or by inhalation Benzoic acid could cause rashes, asthma, inflammation of the mucus membranes of the nose, or anaphylactic shock.

It was also reported that the level of skin reaction on humans was dependent on the pre-existing health condition of the individual. The symptoms lasted for just a few hours.

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On a long term, repeated exposure to benzoic acid causes chronic skin conditions and allergies.

Still researching into the health effects, a group of volunteers were given 1,000, 1,500, 2,000, or 2,500 mg/day of benzoic acid for 5 days each.

The volunteers experienced discomfort, nausea, headache, weakness, burning and irritation of the esophagus. However, given 300 to 400 mg per day for up to 62 days, the lab result showed no abnormalities in blood, urine or nitrogen balance.

Benzoic Acid

A while ago there was panic in Nigeria over the dangers of taking soft drinks with vitamin C. The amount of the benzoic acid contained in the soft drink seemed to be the bone of contention.

Before the panic, several studies including the International Agency for Research on Cancer (IARC) of the World Health Organisation (WHO) said that soft drinks containing a mixture of the salt of benzoic acid, sodium benzoate and vitamin C can cause cancer and other chronic conditions.

According to Dr. Oliver C. Ezechi, the Deputy Director Research, Nigerian Institute of Medical Research, the climate of a given location plays a part in the regulatory quantity permitted in the area. It was an oversight that no consideration was paid to the climatic differences of other countries before exporting the products there.

But as far as Nigeria was concerned, he said:

“Benzoic acid level less than 200mg/kg is in carbonated drinks produced by NBC, which is below the regulatory limits, benzoic acid is safe.”

Safety Measures When Using Benzoic Acid in the Industrial premise include:

  • Proper washing of hands after coming i contact with the acid
  • Avoid contact with eyes, skin, and clothing
  • Proper ventilation of the work space
  • Reduced dust generation and accumulation
  • Thorough cleaning of work clothes
  • Avoid breathing dust

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