Since ancient times, herbs have been used as natural treatments for various illnesses, including viral infections.

Due to their concentration of potent plant compounds, many herbs help fight viruses and are favored by practitioners of natural medicine.

At the same time, the benefits of some herbs are only supported by limited human research, so you should take them with a grain of salt.

Here are 15 herbs with powerful antiviral activity.

Oregano is a popular herb in the mint family that’s known for its impressive medicinal qualities. Its plant compounds, which include carvacrol, offer antiviral properties.

In a test-tube study, both oregano oil and isolated carvacrol reduced the activity of murine norovirus (MNV) within 15 minutes of exposure (1).

MNV is highly contagious and the primary cause of stomach flu in humans. It is very similar to human norovirus and used in scientific studies because human norovirus is notoriously difficult to grow in laboratory settings (2).

Oregano oil and carvacrol have also been shown to exhibit antiviral activity against herpes simplex virus type-1 (HSV-1); rotavirus, a common cause of diarrhea in infants and children; and respiratory syncytial virus (RSV), which causes respiratory infections (3, 4, 5).

Also a member of the mint family, sage is an aromatic herb that has long been used in traditional medicine to treat viral infections (6).

The antiviral properties of sage are mostly attributed to compounds called safficinolide and sage one, which are found in the leaves and stem of the plant (7).

Test-tube research indicates that this herb may fight human immunodeficiency virus type 1 (HIV-1), which can lead to AIDS. In one study, sage extract significantly inhibited HIV activity by preventing the virus from entering target cells (8).

Sage has also been shown to combat HSV-1 and Indiana vesiculovirus, which infects farm animals like horses, cows, and pigs (9, 10).

Many types of basil, including the sweet and holy varieties, may fight certain viral infections.

For example, one test-tube study found that sweet basil extracts, including compounds like apigenin and ursolic acid, exhibited potent effects against herpes viruses, hepatitis B, and enterovirus (11).

Holy basil, also known as tulsi, has been shown to increase immunity, which may help fight viral infections.

In a 4-week study in 24 healthy adults, supplementing with 300 mg of holy basil extract significantly increased levels of helper T cells and natural killer cells, both of which are immune cells that help protect and defend your body from viral infections (12).

Fennel is a licorice-flavored plant that may fight certain viruses.

A test-tube study showed that fennel extract exhibited strong antiviral effects against herpes viruses and parainfluenza type-3 (PI-3), which causes respiratory infections in cattle (13).

What’s more, trans-anethole, the main component of fennel essential oil, has demonstrated powerful antiviral effects against herpes viruses (14).

According to animal research, fennel may also boost your immune system and decrease inflammation, which may likewise help combat viral infections (15).

Garlic is a popular natural remedy for a wide array of conditions, including viral infections.

In a study in 23 adults with warts caused by human papillomavirus (HPV), applying garlic extract to affected areas twice daily eliminated the warts in all of them after 1–2 weeks (16, 17).

Additionally, older test-tube studies note that garlic may have antiviral activity against influenza A and B, HIV, HSV-1, viral pneumonia, and rhinovirus, which causes the common cold. However, current research is lacking (18).

Animal and test-tube studies indicate that garlic enhances immune system response by stimulating protective immune cells, which may safeguard against viral infections (19).

Lemon balm is a lemony plant that’s commonly used in teas and seasonings. It’s also celebrated for its medicinal qualities.

Lemon balm extract is a concentrated source of potent essential oils and plant compounds that have antiviral activity (20).

Test-tube research has shown that it has antiviral effects against avian influenza (bird flu), herpes viruses, HIV-1, and enterovirus 71, which can cause severe infections in infants and children (8, 20, 21, 22, 23).

Peppermint is known to have powerful antiviral qualities and commonly added to teas, extracts, and tinctures meant to naturally treat viral infections.

Its leaves and essential oils contain active components, including menthol and rosmarinic acid, which have antiviral and anti-inflammatory activity (24).

In a test-tube study, peppermint-leaf extract exhibited potent antiviral activity against respiratory syncytial virus (RSV) and significantly decreased levels of inflammatory compounds (25).

Rosemary is frequently used in cooking but likewise has therapeutic applications due to its numerous plant compounds, including oleanolic acid (26).

Oleanolic acid has displayed antiviral activity against herpes viruses, HIV, influenza, and hepatitis in animal and test-tube studies (27).

Plus, rosemary extract has demonstrated antiviral effects against herpes viruses and hepatitis A, which affects the liver (28, 29).

Echinacea is one of the most popularly used ingredients in herbal medicine due to its impressive health-promoting properties. Many parts of the plant, including its flowers, leaves, and roots, are used for natural remedies.

In fact, Echinacea purpurea, a variety that produces cone-shaped flowers, was used by Native Americans to treat a wide array of conditions, including viral infections (30).

Several test-tube studies suggest that certain varieties of echinacea, including E. pallida, E. angustifolia, and E. purpurea, are particularly effective at fighting viral infections like herpes and influenza (31).

Notably, E. purpurea is thought to have immune-boosting effects as well, making it particularly useful for treating viral infections (30).

Sambucus is a family of plants also called elder. Elderberries are made into a variety of products, such as elixirs and pills, that are used to naturally treat viral infections like the flu and common cold.

A study in mice determined that concentrated elderberry juice suppressed influenza virus replication and stimulated immune system response (32).

What’s more, in a review of 4 studies in 180 people, elderberry supplements were found to substantially reduce upper respiratory symptoms caused by viral infections (33).

Licorice has been used in traditional Chinese medicine and other natural practices for centuries.

Glycyrrhizin, liquiritigenin, and glabridin are just some of the active substances in licorice that have powerful antiviral properties (34).

Test-tube studies demonstrate that licorice root extract is effective against HIV, RSV, herpes viruses, and severe acute respiratory syndrome-related coronavirus (SARS-CoV), which causes a serious type of pneumonia (35, 36, 37).

Astragalus is a flowering herb popular in traditional Chinese medicine. It boasts Astragalus polysaccharide (APS), which has significant immune-enhancing and antiviral qualities (38).

Test-tube and animal studies show that astragalus combats herpes viruses, hepatitis C, and avian influenza H9 virus (39, 40, 41, 42).

Plus, test-tube studies suggest that APS may protect human astrocyte cells, the most abundant type of cell in the central nervous system, from infection with herpes (38).

Ginger products, such as elixirs, teas, and lozenges, are popular natural remedies — and for good reason. Ginger has been shown to have impressive antiviral activity thanks to its high concentration of potent plant compounds.

Test-tube research demonstrates that ginger extract has antiviral effects against avian influenza, RSV, and feline calicivirus (FCV), which is comparable to human norovirus (43, 44, 45)

Additionally, specific compounds in ginger, such as gingerols and zingerone, have been found to inhibit viral replication and prevent viruses from entering host cells (46).

Ginseng, which can be found in Korean and American varieties, is the root of plants in the Panax family. Long used in traditional Chinese medicine, it has been shown to be particularly effective at fighting viruses.

In animal and test-tube studies, Korean red ginseng extract has exhibited significant effects against RSV, herpes viruses, and hepatitis A (47, 48, 49).

Plus, compounds in ginseng called ginsenosides have antiviral effects against hepatitis B, norovirus, and coxsackieviruses, which are associated with several serious diseases — including an infection of the brain called meningoencephalitis (49).

Dandelions are widely regarded as weeds but have been studied for multiple medicinal properties, including potential antiviral effects.

Test-tube research indicates that dandelion may combat hepatitis B, HIV, and influenza (50, 51, 52).

Moreover, one test-tube study noted that dandelion extract inhibited the replication of dengue, a mosquito-borne virus that causes dengue fever. This disease, which can be fatal, triggers symptoms like high fever, vomiting, and muscle pain (53, 54).

Herbs have been used as natural remedies since ancient times.

Common kitchen herbs, such as basil, sage, and oregano, as well as lesser-known herbs like astragalus and sambucus, have powerful antiviral effects against numerous viruses that cause infections in humans.

It’s easy to add these powerful herbs to your diet by using them in your favorite recipes or making them into teas.

However, keep in mind that most research has been conducted in test tubes and animals using concentrated extracts. Therefore, it’s unclear whether small doses of these herbs would have the same effects.

If you decide to supplement with extracts, tinctures, or other herbal products, consult your healthcare provider to ensure safe usage.