A daily liquorice habit is being blamed in the case of a 56-year-old woman who ended up in a Dublin hospital suffering from headaches, disturbed vision and a seizure.

Frequent liquorice consumption is a possible cause of the severe though short-lived symptoms experienced by the woman, according to the doctors who treated her at St Vincent’s hospital in Dublin.

The woman revealed to the medical team in recent months she had “habitually” eaten liquorice sweets each day as they were on “special offer” in her local shop.

‘Thunderclap’ headache

She also reported seeing “zig-zag lines and then more vivid colours” in her right visual field. While in the emergency department she had a seizure lasting 60 seconds.

The doctors diagnosed her with posterior reversible encephalopathy syndrome (PRES) associated with liquorice consumption and advised her to avoid further consumption of the sweets, according to a report in the Irish Journal of Medical Science.

PRES is a medical emergency involving headaches, altered mental status, seizures and blurred vision and has a variety of causes. The study says the woman’s case is only the fourth such case associated with liquorice consumption. The authors, from the hospital’s neurology department, say that liquorice contains glycyrrhizic acid, a sweet-tasting substance that can cause water retention and loss of potassium, as well as triggering PRES.

The woman’s symptoms improved within 24 hours and were completely resolved after three weeks.

The US Food and Drug Administration has said foods containing liquorice and its derivatives are safe if not consumed excessively.