Parietaria: use, properties, and tradition

Published on December 16, 2020 - Medicinal Plants

Parietaria officinalis L., belonging to the Urticaceae family, is a herbaceous plant native throughout Italy, from sea level up to 900 meters. It thrives on old walls, rocks, along hedges, in woods, and in dry locations.

The name Parietaria comes from the Latin “paries = wall“, as it is a plant that grows on walls and old structures.

It’s also known as “erba vetriola” for its use in cleaning the insides of bottles and glass in general.

Galen, in the sixth book of his “Virtues of Simple Medicines,” notes its astringent virtue on glass vessels (astringent meaning it cleans, dries, and removes).

In the 18th century, Platearius wrote, “When dry, it has no strength, but when green, it is powerful, since it is diuretic and aperitif”.

Two widely distributed varieties in our territory, belonging to the Parietaria genus, are “judaica” (P. judaica Auct. an L. or P. diffusa M.et K. or P. ramiflora Moench) and “erecta” (P. Parietaria officinalis L. or P. erecta M. et K.), which are therapeutically identical.

A perennial plant, reaching up to 1 meter in height; Parietaria is rhizomatous, with reddish pubescent stems.

The leaves are alternate, stipulate, entire, and lanceolate-oval. The stems are erect or prostrate, rough, woody, and reddish in color.

It has inflorescences composed of a female flower, surrounded by 4-5 male or hermaphrodite flowers, protected by 4 elliptical bracts, entire or fringed, grouped in bundles at the leaf axils.

The fruits are small, black, elliptical, and compressed achenes; each containing a single seed covered by the persistent floral envelope.

The entire plant is covered with dense, straight or curved, rather rigid but non-stinging or prickly hairs.

For herbal purposes, the whole plant is used, excluding the roots.

Active Ingredients: Mucilage, bitter substances, flavonoids, tannins, potassium nitrates, which are believed to be absorbed from old walls where it thrives, sulfur compounds, glycolic, and glyceric acid.

Main Activities: Diuretic, cutaneous purifier, emollient, anti-rheumatic, and anti-inflammatory.

Use: Kidney and bladder stones, cystitis, acute rheumatism, hemorrhoids, skin infections, anemia, bronchitis, and cough. The plant is part of preparations with purifying action combined with other plants with diuretic, uricosuric, etc., properties.

It treats dry and chronic coughs; in powder form, it was used in veterinary medicine for respiratory issues in farm animals. It clears obstructions in the liver, spleen, and kidneys; cleanses the intestines and uterus. It is a diuretic, emmenagogue; alleviates bladder and uterine spasms. Externally, it is used for its anti-inflammatory, soothing, and healing properties, recommended for herpetic sores, burns, and inflammations of mucous membranes and the upper respiratory tract. Its poultices are used against some chronic skin conditions.

In popular use, applying scalded leaves in boiling water was common for burns.

Parietaria pollen can cause allergic rhinitis and asthma in sensitive individuals. The allergy is related to pollen, not to decoctions or hydroalcoholic extracts produced from it, as the allergen denatures.

Internal Use: Urinary tract conditions (stone formation, oliguria, nephritis, cystitis, nephritic colic); biliary and hepatic lithiasis; rheumatism.

External Use: Hemorrhoids and bruises.

In phytoalimurgy (use of plant species for food), young spring shoots are used for preparing soups, boiled water, creams, omelets, and fillings, resulting in an intense green color. It’s also used to make green pasta.

However, caution should be exercised in its consumption, always in small quantities and combined with other vegetables, due to its high oxalate content.