Parsley Becomes Toxic After Flowering

Parsley is a biennial herb, meaning its life cycle spans two years. While safe for consumption in its first year and in its second year before flowering, it becomes toxic once it begins to bloom. In 2023, parsley was named the Poisonous Plant of the Year in Germany due to this characteristic.

The Rise of Apiol Content

Parsley naturally contains a substance called Apiol. In the plant’s first year and before it flowers in the second, the concentration of this compound is harmless. However, once the plant begins to produce flowers, the Apiol level rises significantly in all parts of the plant—stems, leaves, and flowers—making it unsafe to eat.

Apiol is a natural, colorless oil that is also found in carrots and celery. Historically, it was used in medicine to induce menstruation or as an abortifacient.

Symptoms of Apiol Poisoning

Ingesting high doses of Apiol can lead to poisoning with a range of symptoms. Depending on the amount consumed, these can include:

• Nausea and vomiting
• Diarrhea
• Dizziness
• Abdominal pain and cramps

Severe poisoning can result in more serious health consequences, such as kidney and liver damage or even central paralysis, potentially requiring hospitalization.

A Warning About Parsley Seeds

The seeds produced by a flowering parsley plant also have a high concentration of Apiol and are toxic. If these seeds are sown, the resulting new plants will be safe to consume during their first year of growth.

Important: Due to their high toxicity, always store parsley seeds in a location that is inaccessible to children.

Best Practice for Safe Consumption

To ensure safety and avoid the risk of poisoning, it is best to treat parsley as an annual plant. Sow new seeds each year in the spring as soon as the ground is free of frost. This guarantees that your parsley will not enter the toxic flowering stage.