Herbal traditions have used these plants for centuries, but we like to go a step further and look at what modern research actually shows. Below are seven herbs in our antiparasite blend, along with a plain-language look at the peer-reviewed studies behind each one.
Oregano (Origanum vulgare)
Oregano essential oil — and its main active compound, carvacrol — has shown dose-dependent activity against Toxoplasma gondii in laboratory (in vitro) studies. Carvacrol is one of the most studied plant compounds for its broad antimicrobial and antiparasitic potential. Ethanolic oregano extracts have also been shown to kill Giardia intestinalistrophozoites — a common cause of intestinal parasitic infection — causing visible structural damage to the parasite. Separately, oregano oil and carvacrol reduced the infectivity of Cryptosporidium parvum, a leading cause of persistent diarrheal disease in children, in human intestinal cell cultures. 🔗 Toxoplasma gondii study (PubMed) · Giardia study (PubMed) · Cryptosporidium study (PubMed)
Walnut Leaf (Juglans regia)
Ethanolic extracts of walnut leaf demonstrated strong anthelmintic (worm-fighting) activity against Ascaridia galli, a common poultry parasite. In vitro testing showed up to 96.5% inhibition of worm motility, and infected chickens given the extract showed measurable reductions in both worm and egg counts. In a mouse model of cerebral malaria, walnut leaf extract significantly reduced Plasmodium berghei parasitemia and protected against brain damage caused by the infection. Walnut leaf and bark extracts have also shown activity against Leishmania major, the parasite responsible for cutaneous leishmaniasis, in vitro. 🔗 Anthelmintic study (PubMed) · Antimalarial study (PubMed) · Antileishmanial study (PMC)
Wormwood (Artemisia absinthium)
True to its name, wormwood has documented anthelmintic activity against gastrointestinal nematodes in sheep. In a mouse model, wormwood extract reduced Plasmodium berghei (malaria) parasitemia by over 94% after four days of treatment, showing good antiplasmodial activity against both drug-resistant and sensitive strains in vitro as well. Separately, ethanolic wormwood extract was shown to kill Leishmania major promastigotes in vitro, the parasite responsible for cutaneous leishmaniasis in humans. 🔗 Anthelmintic study (PubMed) · Antimalarial study (PubMed) · Antileishmanial study (PubMed)
Rosemary (Rosmarinus officinalis)
A broader literature review of medicinal plants with antiparasitic properties singled out rosemary as one of the species with consistent, published evidence of antiparasitic activity, adding weight to its long history of traditional use. Rosemary essential oil has also been tested directly against Leishmania major, the parasite responsible for cutaneous leishmaniasis in humans, showing measurable activity against the parasite in its infective (promastigote) stage. In a mouse model of chronic toxoplasmosis, a mixture of rosemary leaf extracts reduced Toxoplasma gondii cyst burden by 81% and cyst viability by 23%, supporting its potential as both a treatment and a preventive measure. 🔗 Antiparasitic review · Leishmania study (PubMed) · Toxoplasmosis study (PubMed)
Sage (Salvia officinalis)
Sage tincture and its isolated compounds showed significant activity against Trypanosoma brucei rhodesiense in vitro — the parasite responsible for African sleeping sickness — highlighting sage's relevance beyond common gut parasites. Methanolic sage leaf extracts also inhibited the growth of Leishmania major in both its promastigote and intracellular amastigote forms, reducing infected macrophage counts significantly compared to untreated controls. In a mouse model of malaria, sage leaf extract produced a dose-dependent reduction in Plasmodium berghei parasitemia, with the highest dose suppressing nearly two-thirds of the parasite load. 🔗 Trypanosomiasis study (PubMed) · Leishmaniasis study (PubMed) · Antimalarial study (PMC)
Thyme (Thymus vulgaris)
Thyme essential oil and its active compound thymol showed strong anthelmintic effects against Haemonchus contortus, a parasite well studied in veterinary research. The extracts inhibited egg hatching, slowed larval development, and reduced larval motility in vitro. A related thyme-family essential oil rich in thymol also inhibited the growth of Giardia lamblia, a common human intestinal parasite, disrupting its adherence and structure. Separately, thymol was shown to be effective in vitro and in vivo against Leishmania infantum, the parasite that causes visceral leishmaniasis. 🔗 Anthelmintic study (PubMed) · Giardia study (PubMed) · Leishmania study (PMC)
Hyssop (Hyssopus officinalis)
Hyssop extracts showed anthelmintic activity against both eggs and larvae of Haemonchus contortus. A separate screening study also identified antiplasmodial activity (relevant to malaria parasites) in hyssop extracts, pointing to a dual mode of antiparasitic action. In mice infected with Leishmania major, topical hyssop extract ointment reduced parasite burden and increased nitric oxide production, a key part of the immune response against the parasite, performing comparably to the standard leishmaniasis drug glucantime. 🔗 Haemonchus contortus study · Antiprotozoal screening (PubMed) · Antileishmanial study
Nettle (Urtica dioica)
Nettle leaf and stem extracts demonstrated significant scolicidal activity against Echinococcus granulosus, killing up to 90.51% of protoscoleces in laboratory testing — a striking result for a plant best known as a nutritive tonic. A separate, more recent study confirmed this dose- and time-dependent protoscolicidal effect using a hydroalcoholic nettle extract. Nettle extract has also shown antileishmanial activity in both lab and animal testing, clearing Leishmania major parasites without harming host cells and shifting the immune response toward one that helps fight the infection. 🔗 Scolicidal study 1 · Scolicidal study 2 · Antileishmanial study (PubMed)
Why This Matters
Each of these herbs has been studied individually for antiparasitic properties — largely in vitro or in animal models, mechanisms that don't always translate directly to the same effects in humans. We combine them because their documented modes of action target parasites at different life stages and through different pathways, from disrupting motility and egg-hatching to direct scolicidal effects.
This post is for educational purposes and summarizes existing scientific literature. It is not medical advice, and our blend is not intended to diagnose, treat, cure, or prevent any disease. Please consult a healthcare provider before using herbal supplements, especially if you have a parasitic infection or underlying health condition.