-
Common Name
Japanese Knotweed
-
Botanical Name
Polygonum cuspidatum
-
Part Used
Root & Rhizome
-
Clinical Summary
-
Monograph
-
Alcohol
40%
-
Dose
20 to 55mL weekly
With a potent source of natural antioxidants, Japanese knotweed is a versatile herb commonly used in chronic conditions involving inflammation, immune imbalance, stealth infections, and poor circulation. Best known in Lyme disease protocols, it supports immune modulation, reduces inflammation, protects blood vessels, and penetrates biofilms, with benefits extending beyond this use.
-
Traditional Use
In traditional Chinese medicine (TCM), this herb has been used for over 2,000 years, first recorded in the Supplementary Records of Famous Physicians during the late Han Dynasty. It is known for clearing heat, detoxifying, improving circulation, eliminating phlegm, and relieving coughs and asthma, thereby supporting overall systemic health. Traditionally, it has been used to treat traumatic injuries, jaundice, chronic infections, nervous disorders, hypertension, bronchitis, thick phlegm, and amenorrhoea from blood stagnation. It also appears in classical formulas for abscesses, burns, and snakebites and is valued for its anti-aging and longevity-promoting effects.
-
Actions
Anti-inflammatory, antioxidant, antimicrobial, antiviral, immunomodulator, neuroprotective, cardioprotective, hepatoprotective, mild laxative, antitumour, adaptogenic, angiogenesis modulator (inhibits abnormal blood vessel formation), oestrogenic (mild), astringent, febrifuge (antipyretic)
-
Indications
• Chronic and stealth infections including tick-borne infections, Lyme disease and co-infections such as Babesia, Bartonella and viral infections and reactivations (e.g. Epstein-Barr virus, herpes, shingles, human papillomavirus), bacterial infections, respiratory tract infections, chronic sinusitis, allergic rhinitis, bronchitis, coughs, common cold, asthma.
• Chronic fatigue, post-viral syndromes, post-treatment Lyme disease syndrome (PTLDS), post- COVID.
• Chronic inflammation, skin conditions associated with systemic inflammation such as rosacea, persistent acne, psoriasis, eczema, acne both internally and as a topical preparation.
• Musculoskeletal pain and joint inflammation including rheumatoid arthritis, psoriatic arthritis, gout, osteoarthritis.
• Cardiovascular disease, hypertension, high cholesterol, atherosclerosis, poor peripheral circulation, endothelial dysfunction, metabolic syndrome, diabetes, vascular inflammation.
• Cardiovascular disease, hypertension, high cholesterol, atherosclerosis, poor peripheral circulation, endothelial dysfunction, metabolic syndrome, diabetes, vascular inflammation.
• Liver support and detoxification, fatty liver disease.
• Menopausal symptoms, painful or delayed menstruation.
• Gastrointestinal disorders including inflammatory bowel diseases, ulcerative colitis, Crohn’s disease, leaky gut syndrome, constipation.
• Microbial dysbiosis including the gut, sinuses and urinary tract
• Cancer adjunct protocols -
Energetics
Slightly cooling, drying, bitter, pungent.
-
Use in Pregnancy
Japanese knotweed should not be used in pregnancy, as advised in TCM pharmacopeias, owing to the herb’s abortifacient effects. The resveratrol content has demonstrated uterine stimulant activity in some animal studies, suggesting a potential risk of stimulating contractions. Additionally, the herb’s oestrogenic compounds, though mild, warrant prudence.
-
Contraindications & Cautions
Autoimmune Conditions: The immunomodulatory effects necessitate careful monitoring in autoimmune disorders, particularly during flares. Start with lower doses and titrate gradually.
Hormone-Sensitive Cancers: The mild oestrogenic effects call for caution in oestrogen-dependent malignancies, including certain breast, ovarian and endometrial cancers and uterine fibroids. Consultation with an oncologist is essential.
Bleeding Disorders: Those with clotting disorders, thrombocytopenia or von Willebrand disease should use Japanese knotweed cautiously, if at all.
Surgery: Discontinue use at least two weeks before scheduled surgeries to minimise bleeding risks.
Potential Gastrointestinal Effects: Some patients may experience mild digestive discomfort, particularly at higher doses.
Gastrointestinal Ulceration: The plant’s anthraquinone content may irritate existing ulcers.
Severe Liver or Kidney Disease: While Japanese knotweed supports liver detoxification, caution is advised in individuals with severe hepatic or renal impairment.
Hypotension: Japanese knotweed may exacerbate low blood pressure, particularly in conjunction with antihypertensive medications.
Allergic Reactions: Though uncommon, allergic responses including skin rashes and respiratory symptoms have been reported, particularly in individuals with known allergies to plants in the Polygonaceae family.
Gallstones: As a cholagogue, Japanese knotweed stimulates bile flow which may pose a risk for people with impacted gallstones or obstructed bile ducts. -
Drug Interactions
Caution with chemotherapeutic agents: Complex interactions are possible so Japanese knotweed should only be used concurrently under an oncologist’s supervision.
Caution with anticoagulants and antiplatelets: Japanese knotweed contains resveratrol which may have antiplatelet activity. There is an increased bleeding risk when combined with warfarin, heparin, aspirin, clopidogrel or other blood thinners. Regular international normalised ratio (INR) (a test to measure the time taken for blood to clot) monitoring is recommended if coadministration is necessary.
Caution with cytochrome P450 substrates: Resveratrol moderately inhibits cytochrome P450 substrates, potentially increasing blood levels of medications metabolised through these pathways. This includes certain statins, antidepressants, calcium channel blockers and immunosuppressants.
Caution with immunosuppressants: Japanese knotweed could interfere with immunosuppressive therapy due to its immunomodulatory properties. Particular caution is warranted with cyclosporine, tacrolimus and sirolimus.
Caution with laxatives: The anthraquinone content may have additive effects with other laxatives, potentially causing excessive bowel evacuation.
Monitor with antihypertensives: Japanese knotweed has been studied for its vasodilatory effects which may lower blood pressure. Possible additive hypotensive effects when combined with ACE inhibitors, beta-blockers or calcium channel blockers. Monitor blood pressure levels to avoid excessive hypotension.
Monitor with hormone replacement therapy (HRT): Resveratrol has been studied for its oestrogenic activity. The clinical significance of this remains unclear. The possible hormonal modulation could affect medications such as oral contraceptives or HRT and requires clinical monitoring for efficacy and side effects.
Monitor with digoxin: There is a theoretical interaction based on Japanese knotweed’s cardiovascular effects. Monitoring digoxin levels is prudent.
Monitor with antidiabetic medications: Resveratrol has been shown to modulate glucose metabolism. Possible additive hypoglycaemic effects when combined with metformin, insulin or sulfonylureas. Monitor blood sugar levels to prevent hypoglycaemia. -
Dietary Information
Vegan Friendly. Gluten and dairy free
-
Substitutes
Andrographis, Cat’s Claw, Turmeric, Baical Scullcap