Pine mouth


Sir, we would like to draw readers' attention to a case of a patient complaining of a bad taste (cacogeusia) – specifically metallogeusia.

A 47-year-old male presented reporting a metallic taste (metallogeusia) and a soapy/woolly sensation to the tongue and lips which persisted for six weeks. His medical history was non-contributory: he had no recent trauma to the head or neck, no paranasal sinus problems, and his social history was also unremarkable – he was a non-smoker, moderate alcohol drinker, and he was neither stressed nor depressed. He denied any change in diet, new medication (over the counter or prescribed) or any herbal supplements. However, he suspected the symptom was attributed to eating Chinese pine nuts. Upon clinical examination no oral abnormality was detected and cranial nerves were grossly intact. The symptoms resolved with no treatment other than avoiding further pine nuts, and he has had no sequelae.

'Pine mouth' appears to be an emerging problem but is relatively benign. Pine nuts are edible seeds and most of those on the market belonging to the Pinus genus. The nuts are consumed in sauces (pesto), salads and desserts. Over the past few years, cases of taste disturbances following the consumption of pine nuts have been reported by food agencies and on public Internet websites, and there is a single full paper in the scientific literature.1 Pine mouth was, however, first noted in 2001 in an abstract from a European medical conference.2

It has been hypothesised that a polyunsaturated fatty acid (Δ5-olefinic acid) in pine nuts becomes oxidised causing the rancid taste. Raw, cooked and processed pine nut have all been implicated.3,4,5 We would be interested to hear of any patients with similar symptoms.


  1. 1

    Munk M D . 'Pine Mouth' syndrome: Ccacogeusia following ingestion of pine nuts (genus: pinus). An emerging problem? J Med Toxicol 2010; 6: 158–159.

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  2. 2

    Mostin M . Taste disturbances after pine nut ingestion. Presented at the XXXVIII Congress of the Society for Clinical Toxicology (abstract). J Emerg Med 2001; 8: 76.

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  3. 3

    Destaillats F, Cruz-Hernandez C, Giuffrida F, Dionisi F . Identification of the botanical origin of pine nuts found in food products by gas-liquid chromatography analysis of fatty acid profile. J Agric Food Chem 2010; 58: 2082–2087.

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    Sharashkin L, Gold M . Pine nuts (pignolia): species, products, markets and potential for US production. In Northern Nut Growers Association 95th Annual Report, Proceeding for the 95th annual meeting, Columbia, Missouri. 16-19 August 2004.

  5. 5

    Pine nuts associated with a bitter aftertaste. 16 July 2009. Accessed at:

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Hampton, R., Scully, C. & Ellison, S. Pine mouth. Br Dent J 210, 151 (2011).

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