Key points
  • Neem has antibacterial and antiviral effects, and topical use has been reported to improve skin problems, but caution is needed for pregnant women and with long-term or high-dose use.
  • Oregano’s carvacrol and thymol are attracting attention as natural antibacterial and antiviral compounds. They can be used in cooked dishes or as essential oils, but be careful with the concentration.
  • Allicin in garlic has strong antibacterial properties; consuming freshly grated garlic, low-temperature cooking, or taking supplements are practical ways to get it.
  • Peppermint can relieve nasal congestion and sinus discomfort, and it’s easy to try by inhalation or topical application.
  • Berberine has been studied for oral antibacterial and metabolic-improving effects, but attention is needed for drug interactions and side effects.

Antibacterial and antiviral effects of natural herbs that are welcome this season

Spring and the changing of seasons often bring an increase in ailments caused by viruses and bacteria. Among the herbs that we can easily incorporate into our daily lives, several are expected to have antibacterial and antiviral properties. In this article, we will clearly introduce the scientific knowledge, home uses, and precautions, focusing on neem, oregano, garlic, peppermint, and berberine, which is gaining attention as a supplement. We will also share methods that we actually tried and found easy to use.

Common herbs and what they do

Neem (Neem) — a multifunctional herb long used in Indian traditional medicine

Neem, also known as Indian lilac, is known to contain components such as limonoids in its leaves and oil. Research suggests antibacterial, antiviral, antiparasitic, and anti-inflammatory effects, and mouse experiments have reported that glycoproteins from neem leaves activate immune cells. For external use, old clinical reports indicate that neem oil and soap were effective for scabies and dermatitis, and animal experiments have shown a reduction in skin aging caused by UV rays. However, it has a bitter taste and strong effects, so pregnant or breastfeeding women and those with specific medical conditions should avoid consumption or consult a doctor. We tried neem soap for a short period, but it was irritating, so we were careful not to let it touch our eyes or mucous membranes.

Oregano — the power of carvacrol and thymol

Oregano, familiar in cooking, contains carvacrol, thymol, rosmarinic acid, and other compounds, and is considered to have natural antibacterial and antioxidant properties. Research suggests that carvacrol has antiviral activity against influenza viruses and respiratory viruses. While enjoying its aroma in cooking, you can also use diluted oregano essential oil for gargling or diluted topical application (always follow the dosage) to relieve throat and nasal discomfort. We don't highly recommend mixing a teaspoon of oregano oil with honey when feeling under the weather, but adding dried herbs to soup is easy.

Garlic (allicin) — how to make use of its raw power

Allicin, found in garlic, is known for its strong antibacterial properties. Allicin is produced when garlic is crushed or grated, so consuming small amounts raw or cooking at low temperatures is recommended. However, it is highly irritating, so those with sensitive stomachs should be careful. Supplements (such as aged garlic) are also an option for incorporating it in an odor-suppressed form. What we tried was mixing chopped garlic with olive oil and putting it on bread, which was easy to continue.

How to use them for respiratory and skin troubles — and our experiences

Using peppermint inhalation and topical application to ease nasal congestion

Menthol, found in peppermint, actually has the effect of improving nasal passages and has long been used to relieve sinus discomfort. Easy methods include steam inhalation (dropping a few drops of essential oil into hot water and inhaling from a distance) or applying diluted oil to the chest or temples. We also tried steam inhalation at the onset of a cold and felt that our breathing became easier. However, be very careful with the concentration for children.

Topical applications of neem and oregano (for skin)

Diluted neem oil and oregano essential oil can be used topically to relieve insect bites and mild dermatitis. Commercially available neem soaps and diluted oregano creams are indeed sold, but it is safe to perform a patch test and confirm that there is no irritation or allergic reaction before use.

Berberine (Berberine) — use in supplements and points to note

Berberine is a plant-derived alkaloid that has long been studied for its antibacterial and metabolic regulatory purposes. Oral intake has been reported to improve blood sugar and blood lipids, and some studies also show antibacterial properties. While it is easily available as a supplement, it is known to interact with drugs due to its effects on drug-metabolizing enzymes and transporters. For example, it may interact with warfarin, some antihypertensive drugs, and immunosuppressants, so those taking regular medication should consult a doctor. In our short-term experience with berberine, we sometimes felt a slight digestive burden, and we recommend adhering to the dosage indicated on the label.

Tips for safe use

  • If you are pregnant or breastfeeding, have a serious chronic condition, or are a child, please consult a physician before use.
  • Do not apply essential oils undiluted to the skin. Always dilute them with a carrier oil and perform a patch test before use.
  • Follow the manufacturer's recommended dosage for supplements, and if you regularly take medications, check whether there is a risk of interaction.
  • Even plant-derived products are not automatically “safe” just because they’re natural. The effects of long-term or high-dose use have not been fully studied for some of them.

Summary

Natural herbs are reliable allies that can help with minor everyday ailments. Neem, oregano, garlic, peppermint, and berberine are all expected to have antibacterial and antiviral properties, and their appeal lies in how easily they can be incorporated into daily life through cooking, topical application, or supplements. We have tried several ourselves and found that, depending on how they are used, they can easily help alleviate symptoms. However, there are precautions regarding safety and interactions, so especially if you are pregnant, have a chronic illness, or take regular medication, please consult a specialist before incorporating them. We recommend starting with a small amount and checking your body's condition and reaction.

Disclaimer: The information in this article is for general informational purposes only and does not constitute medical advice. Please consult a qualified healthcare professional before making any health-related decisions.