# Cowslip (Primula veris)

*Key of heaven, fairy cups, key flower, herb Peter, paigle; *Herba paralysis**

**Known today as.** *Primula veris*. An early-spring meadow flower related to the primrose, its yellow blooms nodding in a one-sided cluster.

Kind: Plant  
Poisoning: Saponin irritation (https://thethinkingpress.org/materia-medica/poisons/saponin)

## What was it used for?

The flowers made into wine and conserves; the root, rich in saponins, used as an expectorant; and the whole plant, once called *Herba paralysis*, applied for palsy and nervous complaints.

## What does modern science say?

Its saponins are mildly expectorant; large doses can cause nausea, and some constituents can provoke allergic skin reactions.

## Pharmacognosy and toxicology

- **primulasaponin**: 5–10 per cent of the root
- **primulaverin**: a phenolic glycoside
- **primin**: a contact allergen, chiefly in the related *P. obconica*

**Mechanism.** The root saponins irritate the stomach lining, and by a vagal reflex thin the bronchial secretions, which is the whole of a saponin expectorant; the flower is milder. Primula dermatitis is the commonest plant allergy of European florists.

**Dose.** The root in excess vomits; otherwise safe. The flower wine is harmless.

**Standing.** EMA monographs (2013) for the root and the flower as expectorants in colds; the root is in the licensed German cough mixture Sinupret.

## What lore surrounds it?

Its folk names, key of heaven, fairy cups, key flower, herb Peter, and paigle, read the drooping flower head as a bunch of keys, the attribute of St. Peter. Pliny already noted its early flowering, the apothecaries of medieval Florence sold it as St. Peter’s herb, and Hildegard of Bingen recorded its use while cautioning that it should be applied outwardly only.

## What did the older authorities say?

**Culpeper.** Venus claims it, under Aries, and “our city dames know well enough the ointment or distilled water of it adds beauty”: the flowers more effectual than the leaves, an ointment of them takes away spots, wrinkles, sunburn, and freckles; they remedy vertigo, “ephialtes, false apparitions, phrensies, falling-sickness, palsies”; the Greeks named them Paralysis because they strengthen the brain and nerves; the conserve, the quantity of a nutmeg every morning.

## Sources

- Wikipedia, “*Primula veris*.”
- Culpeper, N. (1653). *The Complete Herbal*, “Cowslips, Or Peagles.” Project Gutenberg #49513.
- EMA/HMPC (2013). *Community herbal monograph on Primula veris L. and/or Primula elatior (L.) Hill, radix* (EMA/HMPC/104095/2012).
- Hausen, B. M. (1978). “On the occurrence of the contact allergen primin in *Primula* species.” *Archives of Dermatological Research* 261.

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*Cowslip.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-10-01. The Thinking Press. https://thethinkingpress.org/materia-medica/cowslip

Historical description, not medical advice.