Red lips, black teeth, and Betel nut toxicity

Red lips, black teeth, and Betel nut toxicity

Arecoline toxicity is rarely seen in the Emergency Department [1]; however, doctors and emergency workers should be aware of this plant and the intoxication it causes. The alkaloids associated with this intoxication are reported in multiple regions of the world. It is important to emphasize how arecoline is the fourth most consumed psychoactive substance after nicotine, ethanol, and caffeine.

What is the “Betel nut”?

The tropical Betel palm (Areca catechu) produces the Betel nut (it is not a fruit but the seed of this plant). The Betel nut contains piperidine alkaloids which have substantial psychostimulating effects. Among these alkaloids, arecoline isprimarily responsible for the muscarinic, nicotinic, and psychostimulating effects of Betel nut consumption. Other alkaloids are arecaine, arecolidine, isoguvacin, and guvacine.

Coloured areca nuts [Areca catechu] in the market. Bago, Burma [Myanmar] It is this red color that determines the color of the spits of the people who consume the “paan” (from: LBM1948 – Wikipedia – CC BY-SA 4.0)

What is the “Betel leaf”?

It is the leaf of a tropical liana belonging to the Piperaceae family. It contains phenolic aromatic compounds, such as cavibetol and cavitol, and in some plants, also a third compound called caditene. Also, it, like the paper of a candy, contain chopped Betel nut mixed with lime (calcium hydroxide, which has a preservative action) and other substances typical of the community that produces it (e.g., tobacco, tamarind, or cardamom)

How is Betel nut consumed?

The Betel nut is thinly cut, combined with lime (to extract the alkaloids), and wrapped in a Piper beetle leaf, giving it its aroma and increasing salivation. It is consumed through chewing, which is usually not accompanied by swallowing, instead being spat out.

Photograph of an areca nut vendor on the island of Hainan, China. (from: Rolfmueller – Wikicommons – CC BY-SA 3.0)

Where is Betel nut chewed?

About 200 million people around the world consume Betel nuts. Primarily produced in Southeast Asia (Myanmar, Thailand, Laos, Cambodia, and Taiwan), it is consumed in Southern China (Yunnan, Xingtan, Hainan Island), Ceylon, Micronesia (Saipan, Guam, Palau, Mariana Islands), Papua, New Guinea, the Indian subcontinent (India, Pakistan, Bangladesh), and the Philippines.

New consumption territories are Melanesia, New Zealand, Australia, and immigrants living in Europe and North America [2].

Why is Betel nut consumed?

The consumption of Betel nut is voluptuous, and the reasons given by consumers are many. In general, it is consumed to “stay awake” and therefore “work harder” and the sensation of heat and energy during chewing. The reasons also include supposed medical and health reasons, such as “strengthening the teeth”, “helping digestion”, and “freshening the breath”. The cultural aspect of its consumption should not be underestimated in Buddhist culture and during some marriage ceremonies in Maharashtra. Betel leaf and Areca nut consumption are common. At the same time, in many countries, it is convivial to consume Betel at the end of the meal.

What is arecoline?

It is a potent agonist of muscarinic and nicotinic receptors [3]. In addition, the calcium hydroxide in the product causes the arecoline to be hydrolyzed into arecaidine, which is a potent inhibitor of Gaba uptake. The result is a strong excitation of the nervous system due to the release of catecholamines (adrenaline and noradrenaline). Pregnant women who chewBetel nuts can transfer the active ingredients via the placenta to the fetus [4].

What are the symptoms of acute Arecoline intoxication?

It is a rare event [5].

The psychological acute arecoline intoxication symptoms are:

  • increased heart rate/palpitations
  • increased systemic pressure
  • increased temperature
  • increased sweating
  • increased salivation
  • nausea, vomiting

In some cases, it can lead to coma, respiratory failure, myocardial infarction.Therefore it is recommended that the patient be monitored closely and treated for cholinergic, neurological, cardiovascular, and gastrointestinal manifestations.

The psychological acute arecoline intoxication symptoms are [6]:

  • well-being
  • euphoria
  • increased alertness
  • increased ability to support hard work
  • feeling of heat

From the EEG point of view, we have widespread cortical desynchronization. So, in case of high consumption, psychosis can arise [7].

Woman with red gingivas chewing paan in Don Det in Laos. Paan is a preparation combining betel leaf with areca nut and tobacco. It is chewed for its stimulant and psychoactive effects. (from: Basile Morin, Wikipedia, CC BY-SA 4.0)

What symptoms does chronic arecoline intoxication give?

Chewing Betel nut leads to discoloration of normal dental enamel, similar to that observed in those who chew tobacco (often Tabac and Betel nut are chewed together). The saliva in the chewing of this nut becomes red and with a markedly alkaline pH. The mucous membranes, gums, and teeth take on this color. Consumption is associated with the development of necrotizing ulcerative gingivitis (ANUG), which is a bacterial infection of the periodontal tissue that can also cause systemic symptoms, such as lymphadenopathy and malaise.

What are the risks of chronic exposure to arecoline?

Betel consumers have an increased risk of cancer of the oropharynx, liver, and uterus [8] . Chronic consumption leads to evident stains on the dental enamel (black tartar) and marked red salivation for the release of tannins. Also, its consumption is predisposing for the development of oropharyngeal carcinoma as nitrogenous compounds deriving from the alkaloids are released. About 60% of oro-pharyngeal cancers occur in areas where people chewed Betel nut.


[1] Deng JF, Ger J, Tsai WJ, Kao WF, Yang CC. Acute toxicities of betel nut: rare but probably overlooked events. J Toxicol Clin Toxicol. 2001;39(4):355-60. doi: 10.1081/clt-100105155. PMID: 11527229.

[2] Nelson BS, Heischober B. Betel nut: a common drug used by naturalized citizens from India, Far East Asia, and the South Pacific Islands. Ann Emerg Med. 1999 Aug;34(2):238-43. doi: 10.1016/s0196-0644(99)70239-8. PMID: 10424931.

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