Benefits, Uses, and Side Effects
Vervain, also known as verbena, Verbena officinalis, and herb of the cross, is a perennial herb native to Europe and Asia (1).
The plant belongs to the Verbenaceae family and has lobed, toothed leaves, and silky, pale-purple flowers. It’s used throughout the world as an herbal remedy because of the multiple beneficial compounds it contains.
This article reviews vervain’s benefits, uses, and potential side effects.
Vervain contains over 20 beneficial plant compounds, including iridoid glycosides, flavonoids, and triterpenoids, which may be responsible for its purported benefits (2).
May possess antitumor effects
Test-tube and animal studies suggest that vervain’s glycosides, triterpenoids, and essential oils may help inhibit tumor growth and induce the death of cancerous cells (3, 4).
In a mouse study, high doses of vervain extract of 18 grams per pound (40 grams per kg) of body weight inhibited tumor growth by more than 30%, compared with controls.
Researchers attributed this anti-tumor activity to verbenosides A and B — two types of glycosides — and triterpenoids (3).
Additionally, citral — a key component in vervain essential oil — possesses proven anticancer effects that cause programmed cell death (5).
One test-tube study found that a concentration of 0.01% vervain essential oil increased the death of rogue immune cells obtained from those with chronic lymphocytic leukemia from 15–52%, suggesting that it may be useful for the development of new therapeutic agents (4).
Nonetheless, human research is needed to verify these claims.
May protect nerve cells
Vervain extract may benefit certain neurological or brain-related conditions.
Studies in rats show that vervain’s glycoside verbenalin — also known as cornin — may significantly improve brain damage after a stroke (6, 7, 8).
The studies explain that the compound promotes the development of new blood vessels in the brain — which supply it with oxygen — and improves its mitochondrial function.
Mitochondria are in charge of energy production in your cells, and they need oxygen to do so. Without oxygen, energy production decreases, leading to issues in regular cellular activity and potentially the development of many diseases of the nervous system (9).
Thus, verbenalin ensures sufficient energy and blood supply to the brain, improving function after a stroke.
What’s more, the extract may protect against the loss of brain cells or neurons in Alzheimer’s disease.
Research suggests that it may reduce the toxicity of beta-amyloid, or Abeta, peptide. The accumulation of this compound is an important toxic factor involved in the development of the disease (10).
May help reduce anxiety and convulsions
Vervain has long been used in folk medicine as a relaxant or nerve tonic, and animal research currently backs up this use.
A study in rats determined that doses of 0.04–0.22 grams per pound (0.1–0.5 grams per kg) of body weight of vervain extract had an anxiety-reducing effect comparable to diazepam, a popular drug used to reduce anxiety (11).
Researchers linked this to the plant’s content of flavonoids and tannins, both of which are known to possess anti-anxiety and sedative properties.
Other studies in rats have concluded that the extract may help manage convulsions or seizures in those with neurological diseases such as epilepsy by prolonging their onset time and shortening their duration (11, 12).
This was attributed to verbenin, an essential component in vervain. Verbenin was even favored over bromide, a compound usually used in epilepsy treatment (11).
May have antimicrobial activity
Antibiotic resistance is a growing global concern. Promisingly, studies show that vervain may protect against antibiotic-resistant bacteria and fungi.
In one test-tube study, vervain essential oil was tested against two fungi and seven bacteria. It inhibited the growth of all microorganisms in a dose-dependent manner — meaning that the higher the dose, the higher the antimicrobial effect (13).
Similarly, another test-tube study demonstrated the antibacterial effect of vervain extract against Staphylococcus aureus, Escherichia coli, and Salmonella typhi, which are responsible for multiple infectious diseases (14).
Compounds in vervain essential oil, such as citral, are known to possess antimicrobial activities. Additionally, other beneficial compounds like flavonoids, which are present in the plant, may add to these effects (15).
Research suggests that flavonoids may inhibit bacterial attachment to the host and neutralize toxicity against human cells. However, studies in humans are still needed (16).
Other beneficial effects
Vervain’s extract and essential oils may provide other potential health benefits, such as:
- Anti-inflammatory activity. The topical use of vervain extract seems to have an anti-inflammatory effect on swelling caused by fluid retention (17).
- Supports gum health. One study in 260 people suggests that a vervain decoction (herbal infusion) may benefit the management of chronic gingivitis or gum inflammation (18).
- Supports heart health. A study in rats determined that treatment with verbenalin, or cornin, reduced heart tissue death and damage from inadequate blood supply (19).
- Antidiarrheal activity. One animal study concluded that vervain root extract significantly delayed the volume and frequency of diarrhea, compared with a control (20).
Vervain is a popular remedy due to its multiple plant-beneficial compounds. Some of its benefits include antitumor effects, nerve cell protection, anxiety- and convulsion-reducing properties, and antimicrobial activity.
Many of vervain’s health benefits are backed by science, but the plant is also used in traditional medicine to treat other ailments without clinical evidence supporting the effects.
For example, in Ethiopia, the leaves are used to treat ear infections, while the root is used to treat tonsils inflammation and ascariasis — a disease caused by the parasite Ascaris lumbricoides that can lead to abdominal pain and diarrhea (21).
The whole plant is also used to treat abdominal pain and to protect against the evil eye, which is believed to cause misfortune or injury (21).
Vervain is also traditionally used as a galactagogue, a substance that increases milk production in breastfeeding women. However, this is another use not supported by scientific evidence (22).
You can find vervain in tincture form, as a powder, or ointment. You can also drink it as an herbal infusion, although it’s said to have a bitter taste.
The flowers are also used as a garnish in cocktails and alcoholic beverages.
Vervain is used in traditional medicine to treat infections and abdominal pain and to promote milk production in breastfeeding women. However, none of those uses are supported by science.
Vervain is generally recognized as safe (GRAS) by the Food and Drug Administration (FDA). While it’s usually well tolerated, there have been reports of side effects (22).
Animal studies show that consuming vervain extract during pregnancy may lead to poor weight gain and fetal abnormalities like reduced bone ossification, or hardening. Thus, pregnant women should avoid all vervain-containing products (23).
Additionally, it’s unknown if compounds from the plant could excrete into breast milk. Therefore, nursing mothers may want to err on the side of caution and avoid consuming the plant to ensure the safety of themselves and their babies (22).
What’s more, older research shows that drinking vervain tea with meals may inhibit iron absorption by 59%. That means people with anemia or iron deficiency should steer clear of the plant (24).
Lastly — and again, according to older research — vervain’s vitamin K content may lead to herb-drug interactions and lessen the effect of blood-thinning drugs like warfarin (25).
Hence, it’s always a good idea to talk with your healthcare provider before trying a new supplement.
Vervain is generally recognized as safe by the FDA. However, pregnant and breastfeeding women, people with iron deficiency, and those taking blood thinners should avoid drinking this tea or consuming any vervain-containing products.
Vervain is a popular herbal remedy used around the world for the treatment of multiple diseases. It may be consumed in the form of tea, tincture, powder, or cream.
It offers multiple health benefits backed by science, including antitumor effects, nerve cell protection, and anxiety- and convulsion-reducing properties, among others.
Just keep in mind that many of its purported benefits and uses are not supported by science, including its use to increase breast-milk production or to treat ear infections.
Lastly, while it’s generally recognized as safe by the FDA, pregnant women, people with anemia, and those taking blood thinners shouldn’t consume it to avoid unwanted side effects.