Plant Comparison
Japanese knotweed vs Elder
A side-by-side comparison of two medicinal plants — every documented constituent, action, use, safety note and cited source, assembled automatically from the Omnia Sana database.
At a glance
Japanese knotweed and Elder: they share 3 indicated uses (arthritis / joint pain, inflammation (general), skin irritation); 2 pharmacological actions in common.
Evidence face-off — shared uses
| Condition | Japanese knotweed | Elder | Verdict |
|---|---|---|---|
| Arthritis / joint pain | 2/10 | 5/10 | Stronger for Elder |
| Inflammation (general) | 7/10 | 5/10 | Stronger for Japanese knotweed |
| Skin irritation | 1/10 | 5/10 | Stronger for Elder |
Evidence scores (1–10) are computed from the tier of each cited source. “Comparable” means the two scores are within one point. Follow a score to its detailed sources.
Key Constituents
Considered the principal bioactive constituents, responsible for much of the antioxidant, anti-inflammatory and cardioprotective activity attributed to this root.
Emodin has laxative and anti-inflammatory activity at typical concentrations but can cause gastrointestinal upset at high doses.
Give the ripe berries their deep colour and much of their antioxidant activity.
Found in both flower and berry, contributing antioxidant and anti-inflammatory activity.
Present in raw berries, leaves, bark and stems; the basis for the caution to always cook berries before eating and avoid raw plant material.
Pharmacological Actions
Traditional & Indicated Uses
inferred from anti-inflammatory action
inferred from anticancer action
inferred from anti-inflammatory action
inferred from anti-inflammatory action
inferred from antiviral action
inferred from anti-inflammatory action
Safety, Cautions & Contraindications
Japanese knotweed root contains resveratrol and emodin; high doses of emodin may cause GI discomfort and have laxative effects. Not recommended during pregnancy (emodin has potential teratogenic effects in animal studies). May interact with anticoagulants and antiplatelet medications. Quality control of commercial preparations is important as invasive weed extracts vary significantly.
Duke (2002) rates Japanese knotweed (listed as Hu-Zhang, Fallopia japonica) as +++ and highlights its rich content of resveratrol and emodin. Experimental evidence (score 1) supports COX-2 inhibitory, antioxidant, anti-inflammatory, hepatoprotective, and lipid-lowering activities — largely attributed to resveratrol. Duke notes its use in traditional Chinese medicine for fractures, burns, abscesses, and gynecological conditions. No significant clinical trials were available at time of publication, but resveratrol's biological activity is well-documented in vitro (Duke, 2002).
The dark blue or purple berries are mildly poisonous in their raw state, but are edible after cooking.https://en.wikipedia.org/wiki/Sambucus_nigra#cite_note-nccih-26https://en.wikipedia.org/wiki/Sambucus_nigra#cite_note-Fagan-2019-28 Components of the elderberry plant, including its fruit, contain diverse https://en.wikipedia.org/wiki/Phytochemical, such as https://en.wikipedia.org/wiki/Alkaloid, https://en.wikipedia.org/wiki/Lectin, and cyanogenic glycosides, which may be toxic if consumed raw.https://en.wikipedia.org/wiki/Sambucus_nigra#cite_note-drugs-8 Consumption of berries, leaves, bark or stems, if not properly prepared, may cause https://en.wikipedia.org/wiki/Nausea, vomiting, and severe https://en.wikipedia.org/wiki/Diarrhea.https://en.wikipedia.org/wiki/Sambucus_nigra#cite_note-nccih-26https://en.wikipedia.org/wiki/Sambucus_nigra#cite_note-drugs-8https://en.wikipedia.org/wiki/Sambucus_nigra#cite_note-msk-27 Elderberry plant constituents or products should not be consumed during pregnancy or by people with https://en.wikipedia.org/wiki/Allergy or https://en.wikipedia.org/wiki/Gastrointestinal_disease.https://en.wikipedia.org/wiki/Sambucus_nigra#cite_note-drugs-8https://en.wikipedia.org/wiki/Sambucus_nigra#cite_note-msk-27 Elderberry products may cause https://en.wikipedia.org/wiki/Adverse_effect when used with https://en.wikipedia.org/wiki/Prescription_drug.https://en.wikipedia.org/wiki/Sambucus_nigra#cite_note-drugs-8https://en.wikipedia.org/wiki/Sambucus_nigra#cite_note-msk-27
Duke (2002) rates elderflower and elderberry as +++ with clinical evidence (score 2) for bronchostimulant, diaphoretic, and secretagogue activities, consistent with Commission E approval. Clinical use for colds, bronchitis, and fever is well-supported. Dose: dried flower: 3–5 g as tea three times daily. Important safety consideration: raw elderberries and elder bark contain sambunigrin (cyanogenic glycoside) and lectins — always cook berries before consumption, and avoid bark preparations for medicinal use without expert guidance (Duke, 2002).
External Ids
Botanical Description
Vigorous, invasive rhizomatous perennial (Polygonaceae) with hollow, bamboo-like, jointed stems 1-3 m tall (occasionally taller), speckled reddish-purple. Leaves are broad, heart- to shovel-shaped with a flat base. Abundant sprays of small, creamy-white flowers appear in late summer, followed by small winged fruit.[6]
Deciduous shrub or small tree (Adoxaceae), 3-10 m tall (occasionally larger), with corky, furrowed grey-brown bark. Leaves are pinnate with 5-7 toothed leaflets. Abundant flat-topped clusters (corymbs) of small, fragrant, creamy-white flowers are followed by drooping clusters of small, glossy, purple-black berries.[11]
Habitat
Native to East Asia (Japan, China, Korea), now a notorious invasive species across Europe and North America, growing in disturbed ground, riverbanks, roadsides and waste land, spreading aggressively via an extensive rhizome network.[6]
Native throughout Europe, western Asia and North Africa, extremely common in hedgerows, woodland edges, waste ground and disturbed sites, tolerating a wide range of soils.[11]
Harvesting
The rhizome/root, the main medicinal part, is dug in autumn or winter when resveratrol content is highest; young spring shoots (stems) are also edible and used. Strict containment is required when harvesting, given the plant's severe invasiveness.[6]
Flowers are picked in full bloom (late spring/early summer), ideally on a dry day, and dried quickly. Berries are picked in late summer/early autumn once fully ripe (deep purple-black) and always cooked before use, as raw berries - and all other parts of the plant - contain cyanogenic glycosides and should not be eaten raw.[11]
Traditional Uses
Known as Hu Zhang in Traditional Chinese Medicine, Japanese knotweed root has a centuries-old use for inflammation, infections, jaundice and menstrual complaints. Modern interest centres on its resveratrol and emodin content, now studied (as Polygonum cuspidatum extract) for antioxidant, anti-inflammatory, cardioprotective and hepatoprotective activity, and more recently for supportive use in acute respiratory infections.[2, 3, 6]
Elder has one of the most celebrated European folk-medicine reputations, described as a 'medicine chest' of the countryside. The flowers have official European herbal-monograph use for symptoms of the common cold, and the berries - cooked, or as a standardised extract - are widely used and clinically studied for upper respiratory and flu-like symptoms.[2, 11]
Preparations
Dried flower steeped in hot water - the classic cold and flu remedy.
Cooked, sweetened berry preparation - the most widely used commercial and traditional form for immune and cold support.
The concentrated form used in influenza clinical trials.
Dosage
Duke (2002) and general phytotherapy guidance treat this as an experimentally supported herb without a single agreed clinical dose; commercial resveratrol-standardised extracts should be dosed per product labelling. Educational reference only, not a prescription; avoid in pregnancy.
References
Lookalikes Review
Dangerous Lookalikes
Not documented
References & Sources
- Dong, X., Fu, J., Yin, X., Cao, S. and others (2016) 'Emodin: A Review of its Pharmacology, Toxicity and Pharmacokinetics', Phytotherapy Research, 30(8), pp. 1207-1218. doi:10.1002/ptr.5631 Traditional / reference
https://doi.org/10.1002/ptr.5631 - Wang, S., Yang, Y., Sun, L., Qiao, G. and others (2022) 'Reynoutria japonica Houtt for Acute Respiratory Tract Infections in Adults and Children: A Systematic Review', Frontiers in Pharmacology, 13, pp. 787032. doi:10.3389/fphar.2022.787032 Meta-analysis / review
https://doi.org/10.3389/fphar.2022.787032 - Ke, Y., Zhan, L., Lu, T., Zhou, C. and others (2023) 'Advances for pharmacological activities of Polygonum cuspidatum (Reynoutria japonica) - A review', Pharmaceutical Biology, 61(1), pp. 177-188. doi:10.1080/13880209.2022.2158349 Traditional / reference
https://doi.org/10.1080/13880209.2022.2158349 - Zhang, Q., Zhao, Y., Zhang, M., Zhang, Y. and others (2021) 'Bioactive amides from Reynoutria japonica', Journal of Asian Natural Products Research, 23(3), pp. 228-234. doi:10.1080/10286020.2021.1873298 Preclinical
https://doi.org/10.1080/10286020.2021.1873298 - Lai, Y., Zhou, C., Huang, P., Dong, Z. and others (2024) 'Polygonum cuspidatum polysaccharide: A review of its extraction and purification, structure analysis, and biological activity', Journal of Ethnopharmacology, 331, pp. 118079. doi:10.1016/j.jep.2024.118079 Traditional / reference
https://doi.org/10.1016/j.jep.2024.118079 - Peng, W., Qin, R., Li, X. and Zhou, H (2013) 'Botany, phytochemistry, pharmacology, and potential application of Polygonum cuspidatum Sieb. et Zucc.: a review', Journal of Ethnopharmacology, 148(3), pp. 729-745. doi:10.1016/j.jep.2013.05.007 Traditional / reference
https://doi.org/10.1016/j.jep.2013.05.007 - Wang, X., Liang, L., Yan, J., Li, Z. and others (2023) 'Citri Reticulatae Pericarpium-Reynoutria japonica Houtt. herb pair suppresses breast cancer liver metastasis by targeting ECM1-mediated cholesterol biosynthesis pathway', Phytomedicine, 116, pp. 154896. doi:10.1016/j.phymed.2023.154896 Preclinical
https://doi.org/10.1016/j.phymed.2023.154896 - Jiang, Y., Liu, Y., Zhang, X. and others (2020) 'New phenolic glycosides from Reynoutria japonica', Journal of Asian Natural Products Research, 22(1), pp. 17-23. doi:10.1080/10286020.2019.1646730 Preclinical
https://doi.org/10.1080/10286020.2019.1646730 - Liu, Y., Wang, J., Li, Q. and others (2024) 'The Possibility of Polygonum cuspidatum against Osteoarthritis based on Network Pharmacology', Current Computer-Aided Drug Design, 20(2), pp. 121-133. doi:10.2174/1573409919666230403114131 Preclinical
https://doi.org/10.2174/1573409919666230403114131 - Espinosa-Andrews, H., Morales-Hernandez, N., Garcia-Marquez, E. and others (2025) 'Physicochemical and rheological characteristics of commercial Greek-style yogurt enriched with Polygonum cuspidatum roots or the P. cuspidatum beta-cyclodextrin inclusion complex', Food Research International, 203, pp. 115854. doi:10.1016/j.foodres.2025.115854 Preclinical
https://doi.org/10.1016/j.foodres.2025.115854 - Burns, J., Yokota, T., Ashihara, H., Lean, M.E.J. and Crozier, A (2002) 'Plant foods and herbal sources of resveratrol', 50(11), pp. 3337--3340. doi:10.1021/jf0112973 Traditional / reference
https://doi.org/10.1021/jf0112973 - Royal Botanic Gardens, Kew (n.d.). Available at: https://powo.science.kew.org Traditional / reference
https://powo.science.kew.org - World Health Organization (2007) 'WHO Monographs on Selected Medicinal Plants'. Traditional / reference
https://scholar.google.com/scholar?q=WHO%20Monographs%20on%20Selected%20Medicinal%20Plants - Duke, J.A (2002) 'Handbook of Medicinal Herbs, Second Edition'. Traditional / reference
https://scholar.google.com/scholar?q=Handbook%20of%20Medicinal%20Herbs%2C%20Second%20Edition
- Liu, D., He, X.Q., Wu, D.T., Li, H.B. and others (2022) 'Elderberry (Sambucus nigra L.): Bioactive Compounds, Health Functions, and Applications', Journal of Agricultural and Food Chemistry, 70(14), pp. 4202-4220. doi:10.1021/acs.jafc.2c00010 Traditional / reference
https://doi.org/10.1021/acs.jafc.2c00010 - Hawkins, J., Baker, C., Cherry, L. and Dunne, E (2018) 'Black elderberry (Sambucus nigra) supplementation effectively treats upper respiratory symptoms: A meta-analysis of randomized, controlled clinical trials', Complementary Therapies in Medicine, 42, pp. 361-365. doi:10.1016/j.ctim.2018.12.004 Meta-analysis / review
https://doi.org/10.1016/j.ctim.2018.12.004 - Uhl, K. and Mitchell, A.E (2024) 'Elderberry, an Ancient Remedy: A Comprehensive Study of the Bioactive Compounds in Three Sambucus nigra L. Subspecies', Annual Review of Food Science and Technology, 15(1), pp. 27-51. doi:10.1146/annurev-food-072023-034423 Traditional / reference
https://doi.org/10.1146/annurev-food-072023-034423 - Asgary, S. and Pouramini, A (2022) 'The Pros and Cons of Using Elderberry (Sambucus nigra) for Prevention and Treatment of COVID-19', Advanced Biomedical Research, 11, pp. 96. doi:10.4103/abr.abr_146_21 Traditional / reference
https://doi.org/10.4103/abr.abr_146_21 - Ferreira, S.S., Martins-Gomes, C., Nunes, F.M. and Silva, A.M (2022) 'Elderberry (Sambucus nigra L.) extracts promote anti-inflammatory and cellular antioxidant activity', Food Chemistry: X, 15, pp. 100437. doi:10.1016/j.fochx.2022.100437 Preclinical
https://doi.org/10.1016/j.fochx.2022.100437 - Dominguez, R., Pateiro, M., Munekata, P.E.S., Santos Lopez, E.M. and others (2021) 'Potential Use of Elderberry (Sambucus nigra L.) as Natural Colorant and Antioxidant in the Food Industry. A Review', Foods, 10(11), pp. 2713. doi:10.3390/foods10112713 Traditional / reference
https://doi.org/10.3390/foods10112713 - Sanlier, N., Ejder, Z.B. and Irmak, E (2024) 'Are the Effects of Bioactive Components on Human Health a Myth?: Black Elderberry (Sambucus nigra L.) from Exotic Fruits', Current Nutrition Reports, 13(4), pp. 815-827. doi:10.1007/s13668-024-00572-6 Traditional / reference
https://doi.org/10.1007/s13668-024-00572-6 - Ulbricht, C., Basch, E., Cheung, L., Goldberg, H. and others (2014) 'An evidence-based systematic review of elderberry and elderflower (Sambucus nigra) by the Natural Standard Research Collaboration', Journal of Dietary Supplements, 11(1), pp. 80-120. doi:10.3109/19390211.2013.859852 Meta-analysis / review
https://doi.org/10.3109/19390211.2013.859852 - Has, I.M., Teleky, B.E., Szabo, K., Simon, E. and others (2023) 'Bioactive Potential of Elderberry (Sambucus nigra L.): Antioxidant, Antimicrobial Activity, Bioaccessibility and Prebiotic Potential', Molecules, 28(7), pp. 3099. doi:10.3390/molecules28073099 Preclinical
https://doi.org/10.3390/molecules28073099 - Kim, J., An, J., Song, Y., Jang, M. and others (2024) 'Effect of Elderberry (Sambucus nigra L.) Extract Intake on Normalizing Testosterone Concentration in Testosterone Deficiency Syndrome Rat Model Through Regulation of 17beta-HSD, 5alpha-Reductase, and CYP19A1 Expression', Nutrients, 16(23), pp. 4169. doi:10.3390/nu16234169 Preclinical
https://doi.org/10.3390/nu16234169 - European Medicines Agency (2018) 'European Union herbal monograph on Sambucus nigra L., flos'. Traditional / reference
https://scholar.google.com/scholar?q=European%20Union%20herbal%20monograph%20on%20Sambucus%20nigra%20L.%2C%20flos - Royal Botanic Gardens, Kew (n.d.). Available at: https://powo.science.kew.org Traditional / reference
https://powo.science.kew.org - Zakay-Rones, Z., Thom, E., Wollan, T. and Wadstein, J (2004) 'Randomized study of the efficacy and safety of oral elderberry extract in the treatment of influenza A and B virus infections', 32(2), pp. 132--140. doi:10.1177/147323000403200205 Randomized trial
https://doi.org/10.1177/147323000403200205 - Duke, J.A (2002) 'Handbook of Medicinal Herbs, Second Edition'. Traditional / reference
https://scholar.google.com/scholar?q=Handbook%20of%20Medicinal%20Herbs%2C%20Second%20Edition - Jimenez, P. and Gayoso, M. and Tejero, J. and Cabrero, P. and Cordoba-Diaz, D. and Basterrechea, J.E. and Girbes, T (2012) 'Toxicity in mice of lectin ebulin f present in dwarf elderberry (Sambucus ebulus L.)', Toxicon, 61, pp. 26-9. doi:10.1016/j.toxicon.2012.10.009 Preclinical
https://doi.org/10.1016/j.toxicon.2012.10.009 - Botanical Society of Britain and Ireland (2023) 'Sambucus ebulus L., dwarf elder (Fermanagh species accounts)'. Available at: https://bsbi.org/in-your-area/local-botany/co-fermanagh/fermanagh-species-accounts/sambucus-ebulus-l Traditional / reference
https://bsbi.org/in-your-area/local-botany/co-fermanagh/fermanagh-species-accounts/sambucus-ebulus-l - Botanical-online (2024) 'Differences between elder and dwarf elder (Sambucus nigra vs Sambucus ebulus)'. Available at: https://www.botanical-online.com/en/botany/differences-sambucus-nigra-ebulus Traditional / reference
https://www.botanical-online.com/en/botany/differences-sambucus-nigra-ebulus
Generated automatically from the Omnia Sana plant database and its cited sources. For educational purposes only — not medical advice. Always consult a qualified practitioner before using medicinal plants.