Thyme for Strep, Herpes, Candida and Flu: What the Evidence Shows

First published March 14, 2017.

Thyme cannot cure strep throat, herpes, a yeast infection or the flu. That is the honest answer to a claim that has circulated on health pages for years. What is true is more modest and still interesting: thyme oil and its main compounds kill many bacteria, fungi and some viruses in laboratory dishes, and thyme preparations have a recognised traditional use for chesty coughs that come with a cold.

The gap between those two statements is where most herbal myths live. Below you will find what thyme is, where the big claims came from, what human studies have actually tested, and how to use the herb safely in the kitchen and the medicine cabinet.

What thyme is and why it smells so strong

Common thyme, Thymus vulgaris, is a small woody shrub from the western Mediterranean and a member of the mint family, Lamiaceae, which also includes oregano, rosemary, sage and basil. Its leaves are rich in an essential oil, and most of that oil's character comes from two related compounds, thymol and carvacrol.

The balance of those compounds differs from plant to plant. Growers sell "chemotypes" of the same species, such as thymol, carvacrol, linalool or thujanol types, which smell different and are used differently. The thymol and carvacrol types are the most potent against microbes and also the most irritating to skin and mucous membranes, which is why aromatherapy suppliers label them for careful, diluted use only.

The name is older than modern chemistry. It comes through Latin from the Greek thymon, a word usually linked to thyein, to burn as an offering or to fumigate. Ancient Greeks burned thyme in temples, and the plant was later used to scent baths and preserve food, so the popular translation "to perfume" is a loose version of a word about fragrant smoke.

Where the claim about killing strep, herpes and flu comes from

The viral claim rests on real laboratory work, stretched far beyond what it shows. Researchers have repeatedly found that thyme oil and thymol stop the growth of bacteria such as Staphylococcus and Streptococcus, yeasts such as Candida, and in some experiments herpes simplex virus. Thymol is strong enough that it is used as an ingredient in some antiseptic mouthwashes and disinfectants.

A test tube is not a throat, a gut or a bloodstream. In the lab, microbes sit directly in a concentrated oil solution. In the body, the same oil would need to reach the infection in an effective dose without harming the tissue around it, and at the concentrations that kill microbes in a dish, thyme oil is irritating or toxic to human cells too. That is why no drug regulator approves thyme to treat any infection.

Some versions of the story mention a French study in which thyme oil killed 90 percent of microbes within three hours, or describe the oil as a surgical hand disinfectant. We could not trace a published study matching that description. Even if it exists, a result about cleaning surfaces or skin says nothing about curing an infection inside a person.

What human studies actually support

The strongest evidence concerns coughs. In the European Union thyme preparations are registered as traditional herbal medicines for productive, chesty coughs associated with colds. The European Medicines Agency is clear that this status rests on at least 30 years of safe use rather than on convincing clinical trials, and most products are meant for adults and children over 12.

There is also some trial evidence for combination products. In a German trial published in 2006, 361 adults with acute bronchitis took either a syrup of thyme and ivy leaf extracts or a placebo for 11 days. Coughing fits fell by about 69 percent in the herbal group and 48 percent in the placebo group, with no difference in side effects. That is a useful result, but it shows the syrup eased a cough that was getting better anyway; it does not show that thyme killed the infection behind it.

The other often-quoted study is a 1998 Scottish trial in 86 people with alopecia areata, a condition that causes patchy hair loss. Participants massaged a blend of thyme, rosemary, lavender and cedarwood oils in jojoba and grapeseed oil into the scalp every day for seven months; 44 percent improved, against 15 percent of those who used the carrier oils alone. It was a single small study that has never been followed by a larger one, so it is a lead rather than a treatment.

Strep, herpes, Candida and flu: what to do instead

Each infection in the headline has a proven treatment, and each can cause harm if it is left to a kitchen remedy.

• Strep throat is a bacterial infection that a quick swab can confirm. Antibiotics shorten it and prevent rare but serious complications such as rheumatic fever, which affects the heart.
• Herpes simplex, whether cold sores or genital herpes, stays in the body for life. Antiviral medicines reduce outbreaks and the chance of passing it on; no herb removes the virus.
• Candida infections, including vaginal thrush and oral thrush, respond well to antifungal creams, pessaries or tablets. Essential oils applied to mucous membranes can cause painful burns.
• Influenza is best prevented with a yearly vaccine. Antiviral drugs help most when started early, especially for older people, pregnant women and those with long-term illnesses.

If you suspect any of these, talk to a doctor or pharmacist. Thyme tea or a thyme cough syrup can sit alongside proper care for comfort, but not in place of it.

The long list of other claimed uses

Posts about thyme often add a list of further benefits. Here is how they hold up:

• Urinary and bladder infections, vaginitis: no clinical evidence; these need diagnosis and standard treatment.
• Nail fungus and athlete's foot: thymol is active against fungi in the lab and appears in a few topical products, but studies of thyme alone are minimal.
• Hand sanitiser: thymol-based disinfectants exist, yet ordinary soap and water or alcohol gels are the tested options.
• Muscle, joint and arthritis pain, sprains, gout, sciatica: massage with any warming oil may feel soothing; there is no good evidence for thyme specifically.
• Acne, warts, insect bites, wound healing: early lab and small pilot studies only.
• Depression, fatigue, insomnia, memory: no reliable human trials.
• Blood pressure: some posts say thyme raises it and others that it lowers it; neither claim has solid human evidence.
• Irregular periods, parasites, hair tonic, higher DHA in organs: based on traditional use or animal work at most.

An herb that is said to fix almost everything usually has strong evidence for almost nothing. That is not a reason to avoid thyme, only a reason to expect less of it.

Safety: the herb and the oil are different things

Thyme in food is safe for nearly everyone. The concentrated essential oil is a different product, and it deserves the same respect as any strong chemical.

• Do not swallow thyme essential oil. Its safety by mouth has not been established, and essential oils are a known cause of poisoning in young children.
• Always dilute it before putting it on skin, keep it away from eyes and mucous membranes, and stop if redness or burning appears.
• People allergic to oregano or other mint-family plants may react to thyme.
• According to WebMD's natural medicines summary, medicinal amounts might slow blood clotting, so people taking anticoagulant or antiplatelet drugs should check first and stop medicinal use two weeks before surgery.
• Pregnant and breastfeeding women should stick to food amounts, and people with hormone-sensitive conditions should ask a doctor, because thyme may have mild oestrogen-like effects.

Using thyme sensibly

The most reliable way to enjoy thyme is still the oldest: as a herb in soups, stews, roast vegetables and marinades, or as a warm tea of fresh or dried sprigs when you have a cold. Breathing steam from hot water with a few sprigs may feel soothing for a blocked nose, although the relief comes mainly from the warm steam itself.

If you want a medicinal product, look for a registered thyme cough syrup or a thyme and ivy combination from a pharmacy, follow the label, and see a doctor if a cough lasts more than three weeks, you cough up blood, or you have a high fever or trouble breathing. Thyme earns its place in the kitchen and has a small, real role for coughs. It is not a cure for strep, herpes, Candida or flu.

Sources: European Medicines Agency, Thymi herba assessment; Kemmerich et al., thyme and ivy syrup in acute bronchitis, Arzneimittel-Forschung 2006; Hay et al., Archives of Dermatology 1998; WebMD, Thyme: uses and safety; the claims examined here circulated on Healthandlovepage.com, Livingtraditionally.com, Naturalnews.com and Healthy Food House.