What to know about Marrubium vulgare (horehound) before using it medicinally

Marrubium vulgare, commonly known as horehound, is a versatile herb that has been revered for its numerous health benefits, including its anti-inflammatory and antimicrobial properties, which have been shown to improve respiratory issues and soothe digestive problems.

As a hardy perennial, Marrubium vulgare is prized for its ease of cultivation and ability to thrive in a variety of soil types and conditions, making it a favorite among gardeners. From a botanical standpoint, the herb belongs to the mint family and is characterized by its oval-shaped leaves and clusters of small, white flowers.

Historically, horehound has been used in traditional medicine for centuries, with references to its use found in ancient Greek and Roman texts, including those by Hippocrates and Pliny the Elder.

This article explains the medicinal, horticultural, botanical, and historical aspects of Marrubium vulgare.

What are the medicinal properties of Marrubium vulgare?

Marrubium vulgare helps with coughs and respiratory issues, such as bronchitis, asthma, and tuberculosis, due to its expectorant and bronchodilator properties. It has also been used to treat digestive problems, including diarrhea, dyspepsia, and stomach ulcers. In traditional medicine, horehound has been used to reduce fever and alleviate headaches.

The active constituents of Marrubium vulgare include marrubiin, rosmarinic acid, and caffeic acid, which are responsible for its medicinal properties. Marrubiin is a phenolic compound with antioxidant and anti-inflammatory effects. Rosmarinic acid has antioxidant and antimicrobial properties. Caffeic acid has antibacterial and antifungal effects.

The parts of the Marrubium vulgare plant most used for medicinal purposes are the leaves and flowers. The leaves are used to make infusions, decoctions, and tinctures, while the flowers are used to make infusions and tinctures. The plant is usually harvested in the summer months when the leaves are mature.

Improper use of Marrubium vulgare can cause side effects, including gastrointestinal upset, nausea, and diarrhea. High doses of the plant can also cause allergic reactions, such as skin irritation and anaphylaxis. Long-term use of horehound can lead to kidney damage and interact with certain medications.

To use Marrubium vulgare medicinally, precautions should be taken, including consulting a healthcare professional before use, especially for pregnant or breastfeeding women. The plant should be used in moderation, as excessive consumption can cause adverse effects. Additionally, individuals with kidney or liver disease should use horehound with caution.

What are the horticulural aspects of Marrubium vulgare?

Marrubium vulgare grow best in well-drained soil with a pH between 6.0 and 7.0. It thrives in full sun to partial shade and can tolerate dry conditions. The plant is hardy in USDA zones 4-9.

For optimal growth, plant horehound in a location with good air circulation. Space plants 12-18 inches apart and water regularly during the first year after planting. Established plants can tolerate some drought, but consistent moisture promotes healthy growth.

Horehound leaves and flowers can be harvested at any time, but the best time is in mid-summer when the leaves are at their peak flavor and the flowers are in full bloom. Cut the stems near the base to promote regrowth, and harvest individual leaves or flowers as needed.

Pests that commonly affect horehound include aphids, whiteflies, and spider mites. Fungal diseases like leaf spot and root rot can also occur, particularly in wet or humid conditions. Regular watering and good air circulation can help prevent these issues, but may not eliminate them entirely.

What are the botanical aspects of Marrubium vulgare?

Marrubium vulgare is a perennial herbaceous plant with a woody base and a branching stem, typically reaching 30-100 cm in height. Leaves are oppositely arranged, oval, and 2-5 cm long, with a grayish-green color and a soft texture. Inflorescences are terminal, axillary, and spicate.

Marrubium vulgare belongs to the family Lamiaceae, and its taxonomical classification is: Kingdom: Plantae, Clade: Angiosperms, Clade: Eudicots, Clade: Asterids, Order: Lamiales, Family: Lamiaceae, Genus: Marrubium, Species: M. vulgare. It is a member of the mint family, with similarities in leaf structure and inflorescence arrangement.

Variants of Marrubium vulgare include Marrubium desertorum, Marrubium alysson, and Marrubium supinum, among others. These variants exhibit subtle differences in leaf shape, flower color, and growth habit, but are otherwise similar to the parent species.

Marrubium vulgare is native to the temperate regions of Europe, Western Asia, and North Africa. It has been naturalized in many parts of the world, including North America, Australia, and South Africa. It thrives in dry, well-drained soils and full sun to partial shade.

The life cycle of Marrubium vulgare begins with seed germination, typically in early spring or fall. The seedling develops a taproot, and eventually produces leaves, stems, and inflorescences. The plant flowers from May to August, producing small, white or blue flowers in axillary spikes. Seeds are produced in late summer, allowing for self-seeding and propagation.

What are the historical aspects of Marrubium vulgare?

Marrubium vulgare is a plant with a long history of use in traditional medicine. In ancient Greece and Rome, it was used to treat a variety of ailments, including coughs, colds, and digestive issues. The plant was also used in folk medicine to reduce fever and relieve pain.

In ancient myth, Horehound was associated with the goddess Diana, who was said to have used it to cure a poisoned deer. The plant was also linked to the myth of the "Hound of Diana", which was said to have been cured of a deadly disease by the goddess's intervention. These mythological references highlight the plant's perceived healing properties.

Horehound has been imbued with symbolic meanings across cultures. In medieval Europe, it was seen as a symbol of protection against evil spirits, while in ancient Greece, it represented good luck and prosperity. In some African cultures, the plant is associated with spiritual growth and transformation.

The historical texts of horehound can be found in ancient medical texts, such as Dioscorides' "De Materia Medica" and the "Ebers Papyrus". These texts describe the plant's medicinal properties and provide instructions for its use in various treatments. The "Physica Plini" also mentions the plant's use in folk medicine.

Historical artifacts associated with horehound include ancient medical instruments, such as mortars and pestles, which were used to prepare horehound infusions. Archaeologists have also discovered ceramic vessels and wooden spoons used to prepare and consume the plant. These artifacts demonstrate the widespread use and importance of horehound in ancient cultures.