Plant Comparison

Pleurisy Root vs Willow Bark

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.

First plant

Second plant

Plant APleurisy RootAsclepias tuberosaApocynaceaeFull monograph →

Plant BWillow BarkSalix albaSalicaceaeFull monograph →

At a glance

Pleurisy Root and Willow Bark: they share 4 indicated uses (arthritis / joint pain, fever, inflammation (general), …); 1 pharmacological action in common.

Pleurisy RootWillow Bark

Constituents22

Pharmacological actions33

Indicated uses87

Safety notes22

Cited sources1413

Indicated uses

Only Pleurisy Root

BronchitisCold & fluCoughRespiratory support

Shared (4)

Arthritis / joint painFeverInflammation (general)Skin irritation

Only Willow Bark

Back painHeadachePain (general)

Pharmacological actions

Only Pleurisy Root

DiaphoreticExpectorant

Shared (1)

Anti-inflammatory

Only Willow Bark

Analgesic (pain relief)Antipyretic (reduces fever)

Evidence face-off — shared uses

Condition	Pleurisy Root	Willow Bark	Verdict
Arthritis / joint pain	1/10	7/10	Stronger for Willow Bark
Fever	1/10	1/10	Comparable evidence
Inflammation (general)	1/10	8/10	Stronger for Willow Bark
Skin irritation	2/10	8/10	Stronger for Willow Bark

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

Cardiac glycosides (cardenolides such as asclepin, calactin and calotropin)^{[11, 12]}

Heart-active compounds that make dosing and safety critical.

Glycosides

Flavonoids and amino acids^[12]

Supporting constituents of the root.

Flavonoids

Salicin and related salicylates^{[1, 2, 6, 7, 11, 12]}

Metabolised in the body to salicylic acid - the 'natural aspirin' that gives the analgesic, anti-inflammatory and antipyretic effects.

Salicin

Polyphenols, flavonoids and tannins^{[10, 12]}

Contribute additionally to the anti-inflammatory and antioxidant activity.

Phenolic compoundsFlavonoidsTannins

Pharmacological Actions

Anti-inflammatory^[12]

Anti-inflammatory for lung inflammation (traditional)

Diaphoretic^{[9, 10, 11, 12]}

Diaphoretic - promotes sweating to support feverish illness

Expectorant^{[9, 10, 11, 12]}

Traditional expectorant - helps clear phlegm in chest conditions, bronchitis and pleurisy

Analgesic (pain relief)^{[1, 8, 9, 11, 12, 13]}

Analgesic and anti-inflammatory for low back pain (moderate evidence; dose-dependent, around 240 mg salicin/day) - in an RCT, 240 mg salicin/day left 39% pain-free vs 6% on placebo within 4 weeks

Anti-inflammatory^{[1, 4, 11, 12, 13]}

Analgesic and anti-inflammatory for low back pain (moderate evidence; dose-dependent, around 240 mg salicin/day) - in an RCT, 240 mg salicin/day left 39% pain-free vs 6% on placebo within 4 weeks

Antipyretic (reduces fever)^[12]

Antipyretic (reduces fever)

Traditional & Indicated Uses

Arthritis / joint pain^[12]Traditional · 1/10

inferred from anti-inflammatory action

Evidence: 1

Label: Arthritis / joint pain

Bronchitis^{[10, 11, 12]}Traditional · 1/10

Traditional expectorant - helps clear phlegm in chest conditions, bronchitis and pleurisy

Evidence: 1

Label: Bronchitis

Cold & flu^{[11, 12]}Traditional · 1/10

inferred from diaphoretic action

Evidence: 1

Label: Cold & flu

Cough^{[11, 12]}Traditional · 1/10

inferred from expectorant action

Evidence: 1

Label: Cough

Fever^{[11, 12]}Traditional · 1/10

inferred from diaphoretic action

Evidence: 1

Label: Fever

Inflammation (general)^[12]Traditional · 1/10

Anti-inflammatory for lung inflammation (traditional)

Evidence: 1

Label: Inflammation (general)

Respiratory support^{[9, 10, 11, 12]}Traditional · 1/10

inferred from expectorant action

Evidence: 1

Label: Respiratory support

Skin irritation^{[7, 12]}Traditional · 2/10

inferred from anti-inflammatory action

Evidence: 2

Label: Skin irritation

Arthritis / joint pain^{[11, 12]}Good · 7/10

Relief of joint pain, osteoarthritis and rheumatic complaints

Evidence: 7

Label: Arthritis / joint pain

Back pain^{[8, 9, 11, 12, 13]}Strong · 9/10

Analgesic and anti-inflammatory for low back pain (moderate evidence; dose-dependent, around 240 mg salicin/day) - in an RCT, 240 mg salicin/day left 39% pain-free vs 6% on placebo within 4 weeks

Evidence: 9

Label: Back pain

Fever^[12]Traditional · 1/10

Antipyretic (reduces fever)

Evidence: 1

Label: Fever

Headache^[12]Traditional · 1/10

Evidence: 1

Label: Headache

Inflammation (general)^{[11, 12, 13]}Good · 8/10

inferred from anti-inflammatory action

Evidence: 8

Label: Inflammation (general)

Pain (general)^{[8, 11, 12, 13]}Strong · 9/10

Analgesic and anti-inflammatory for low back pain (moderate evidence; dose-dependent, around 240 mg salicin/day) - in an RCT, 240 mg salicin/day left 39% pain-free vs 6% on placebo within 4 weeks; Relief of joint pain, osteoarthritis and rheumatic complaints

Evidence: 9

Label: Pain (general)

Skin irritation^{[11, 12, 13]}Good · 8/10

inferred from anti-inflammatory action

Evidence: 8

Label: Skin irritation

Safety, Cautions & Contraindications

Safety note^{[8, 11, 12]}Caution

Contains cardiac glycosides: do NOT use in pregnancy, breastfeeding or infancy, in anyone with a heart condition, or alongside cardiac glycoside medicines (e.g. digoxin). The plant's cardenolide-rich latex is directly toxic - a documented case caused corneal injury through Na/K-ATPase inhibition.

Safety note^[12]Info

Large doses are emetic and purgative (cause vomiting and diarrhoea). There is very little modern safety or efficacy data, so use only under the guidance of a qualified practitioner.

Safety note^[12]Caution

Because it works like aspirin, avoid willow bark if you are allergic to aspirin or salicylates, and do NOT give it to children or teenagers with a viral illness (risk of Reye's syndrome). Use caution in asthma (salicylate sensitivity).

Safety note^[12]Caution

Avoid with anticoagulant/antiplatelet medicines (bleeding risk) and in active peptic ulcer; avoid in pregnancy (especially the third trimester) and breastfeeding.

External Ids

Gbif: 3170305

Wikidata: Q311131

Wikidata: Q156918

Botanical Description

Erect perennial herb with hairy, unbranched stems and narrow, lance-shaped, alternate leaves (unlike most milkweeds, its sap is clear rather than milky). Vivid orange-red flowers are borne in showy, flat-topped umbel-like clusters at the stem tips, making it a prized butterfly and pollinator plant. The stout, fibrous, branching root is the medicinal part.^[11]

Height: 30-90 cm

Habit: Erect, hairy perennial herb

Leaves: Narrow, lance-shaped, alternate

Flowers: Vivid orange-red flowers in showy, flat-topped umbel-like clusters

Stem: Erect, hairy, unbranched, exuding clear (not milky) sap when cut

Root: Stout, fibrous, branching taproot

Fruit: Spindle-shaped seed pod (follicle) releasing silky-tufted seeds

Flowering Period: June-September

Large deciduous tree (Salicaceae), 10-25 m tall (occasionally taller), fast-growing with a broad crown. Leaves are narrow and lance-shaped, silvery-white and silky-hairy beneath, giving the tree a shimmering appearance in the wind. Tiny flowers are borne in catkins appearing with the leaves in spring; the species is dioecious. The fruit is a small capsule releasing cottony-tufted seeds.^[12]

Height: 10-25 m

Habit: Large, fast-growing deciduous tree, dioecious

Leaves: Narrow, lance-shaped, silvery-white and silky-hairy beneath

Flowers: Tiny, in catkins with the leaves

Stem: Broad-crowned trunk

Root: Extensive, water-seeking root system

Fruit: Small capsule with cottony-tufted seeds

Flowering Period: April-May

Habitat

Native to dry prairies, open fields, roadsides and sandy or rocky open ground across most of eastern and central North America.^[11]

Native to Europe, western and central Asia and North Africa, growing on damp ground along riverbanks, floodplains and wet meadows; widely planted and naturalised elsewhere.^[12]

Harvesting

The root is dug in autumn after the plant has finished flowering and seeding, then cleaned and dried; given its cardiac glycoside content and near-absence of modern safety data, harvesting and use should only be undertaken with expert guidance.^[11]

Parts: Root

Season: Autumn

Bark is stripped from young branches (2-3-year-old growth is preferred, as salicin content is highest in younger bark) in spring, when the rising sap makes the bark peel most easily, then dried.^[12]

Parts: Bark

Season: Spring

Traditional Uses

Pleurisy root has a Native American and Eclectic-medicine reputation, reflected in its name, as an expectorant and diaphoretic for chest complaints, bronchitis and pleurisy, used to promote sweating during feverish illness and help clear phlegm.^{[11, 12]}

Willow bark has one of the longest documented histories of any medicinal plant, used since antiquity (recorded by Hippocrates) as a remedy for pain and fever. Its salicin content, chemically related to aspirin, gives it official European herbal-monograph recognition for mild joint pain, headache and feverish colds, with modern clinical trials supporting benefit for low back pain.^{[11, 12]}

Preparations

Decoction^[11]

Dried root simmered in water as a traditional expectorant and diaphoretic remedy; given its cardiac glycoside content, only under qualified practitioner guidance.

Decoction^[12]

Dried bark simmered in water - the traditional preparation, since salicin needs proper simmering (not just a quick infusion) to extract well.

Standardised extract (capsule/tablet)^[11]

Standardised to salicin content, the form used in clinical trials.

Dosage

All preparations^[12]

Because the root contains cardiac glycosides and modern safety/efficacy data are very limited, no general dose is given here; use only under the guidance of a qualified practitioner, and never in pregnancy, breastfeeding, infancy, or with a heart condition or cardiac glycoside medicines. Educational reference only, not a prescription.

Standardised extract^{[11, 12]}

Clinical trials for back pain have used around 240 mg salicin/day of standardised extract. Educational reference only, not a prescription; avoid if allergic to aspirin/salicylates, in children/teenagers with a viral illness (Reye's syndrome risk), or alongside anticoagulants.

References

REF-0734, REF-0738, REF-0735, REF-1944, REF-1945, REF-1946, REF-1947, REF-0626, REF-1948, REF-1949

REF-1253, REF-1254, REF-1255, REF-1256, REF-1257, REF-1258, REF-1259, REF-1260, REF-1261, REF-1262

Lookalikes Review

Outcome: has-lookalikes

Reviewed By: Omnia Sana (owner-authorized)

Reviewed Date: 2026-07-07

Outcome: none-known

Reviewed By: Omnia Sana (owner-authorized)

Reviewed Date: 2026-07-07

Dangerous Lookalikes

Safety note^{[13, 14]}Dangerous

Dangerous Plant: apocynum-cannabinum

Confused Part: Young shoots (and the root) gathered from the wild; toxic dogbane sends up very similar shoots in the same habitat.

Confusion Context: Butterfly weed / pleurisy root (Asclepias tuberosa) is a milkweed whose young shoots and root have been used. Its main dangerous look-alike is dogbane (Apocynum cannabinum): at the shoot stage the two are easily confused and grow in similar places. Dogbane is a high-severity poison - its milky sap contains cardiac glycosides, all parts are toxic to humans, and poisoning can cause vomiting, weakness and cardiac arrest, while the sap blisters skin. Because the young shoots look alike, the bitterness test below matters.

Distinguishing Features: Taste/bitterness (decisive): dogbane is horribly, intensely bitter - an immediate warning to spit it out; edible milkweed shoots are not. Never swallow a bitter 'milkweed' shoot., Growth habit: dogbane shoots are thinner and firmer and branch early; milkweeds do not branch at the shoot stage. An early-branching, thin, firm shoot is likely dogbane., General: both milkweeds and dogbane have milky sap, so sap alone does not distinguish them - rely on bitterness and branching, and confirm the species before eating.

Key Test: Taste a tiny piece and check the branching (then spit it out). An intensely bitter shoot, or one that is thin, firm and branches early, is dogbane - toxic, do not eat. Milky sap alone does not prove it is safe; if in any doubt, discard it.

Reviewed By: Omnia Sana (owner-authorized)

Reviewed Date: 2026-07-07

Not documented

References & Sources

Warashina, T. and Miyase, T (2017) 'New 8,12;8,20-diepoxy-8,14-secopregnane hexa- and hepta-glycosides from the roots of Asclepias tuberosa', Journal of Natural Medicines, 72(1), pp. 347-356. doi:10.1007/s11418-017-1155-9 Preclinical
https://doi.org/10.1007/s11418-017-1155-9
Abe, F. and Yamauchi, T (2000) 'An androstane bioside and 3'-thiazolidinone derivatives of doubly-linked cardenolide glycosides from the roots of Asclepias tuberosa', Chemical & Pharmaceutical Bulletin, 48(7), pp. 991-993. doi:10.1248/cpb.48.991 Preclinical
https://doi.org/10.1248/cpb.48.991
Lockwood, T.L (1848) 'Asclepias Tuberosa, Butterfly-Weed, Milk-Weed, Pleurisy Root, White Root', The Medical Examiner (Philadelphia), 4(42), pp. 367-368. Available at: https://pubmed.ncbi.nlm.nih.gov/38120955/ Traditional / reference
https://pubmed.ncbi.nlm.nih.gov/38120955/
Abe, F. and Yamauchi, T (2000) 'Pregnane glycosides from the roots of Asclepias tuberosa', Chemical & Pharmaceutical Bulletin, 48(7), pp. 1017-1022. doi:10.1248/cpb.48.1017 Preclinical
https://doi.org/10.1248/cpb.48.1017
Warashina, T. and Noro, T (2009) '8,14-Secopregnane glycosides from the aerial parts of Asclepias tuberosa', Phytochemistry, 70(10), pp. 1294-1304. doi:10.1016/j.phytochem.2009.07.033 Preclinical
https://doi.org/10.1016/j.phytochem.2009.07.033
Warashina, T. and Noro, T (2010) '8,12;8,20-Diepoxy-8,14-secopregnane glycosides from the aerial parts of Asclepias tuberosa', Chemical & Pharmaceutical Bulletin, 58(2), pp. 172-179. doi:10.1248/cpb.58.172 Preclinical
https://doi.org/10.1248/cpb.58.172
Warashina, T., Umehara, K., Miyase, T. and Noro, T (2011) '8,12;8,20-diepoxy-8,14-secopregnane glycosides from roots of Asclepias tuberosa and their effect on proliferation of human skin fibroblasts', Phytochemistry, 72(14-15), pp. 1865-1875. doi:10.1016/j.phytochem.2011.05.012 Preclinical
https://doi.org/10.1016/j.phytochem.2011.05.012
Mikkelsen, L.H., Hamoudi, H., Gul, C.A. and Heegaard, S (2017) 'Corneal Toxicity Following Exposure to Asclepias Tuberosa', The Open Ophthalmology Journal, pp. 1--4. doi:10.2174/1874364101711010001 Preclinical
https://doi.org/10.2174/1874364101711010001
Lockwood, T.L (1848) 'Asclepias Tuberosa, Butterfly-Weed, Milk-Weed, Pleurisy Root, White Root', Medical Examiner (Philadelphia), 4(42), pp. 367-368. Traditional / reference
https://scholar.google.com/scholar?q=Asclepias%20Tuberosa%2C%20Butterfly-Weed%2C%20Milk-Weed%2C%20Pleurisy%20Root%2C%20White%20Root
Lockwood, T.T (1848) 'Asclepias Tuberosa, Butter-Fly-Weed, Milk Weed, Pleurisy Root, White Root', Buffalo Medical Journal and Monthly Review, 3(10), pp. 600-602. Traditional / reference
https://scholar.google.com/scholar?q=Asclepias%20Tuberosa%2C%20Butter-Fly-Weed%2C%20Milk%20Weed%2C%20Pleurisy%20Root%2C%20White%20Root
The Naturopathic Herbalist (n.d.) 'Asclepias tuberosa'. Available at: https://thenaturopathicherbalist.com/2015/09/06/asclepius-tuberosa/ Traditional / reference
https://thenaturopathicherbalist.com/2015/09/06/asclepius-tuberosa/
Herbs2000 (n.d.) 'Pleurisy Root (Asclepias tuberosa)'. Available at: https://www.herbs2000.com/herbs/herbs_pleurisy_root.htm Traditional / reference
https://www.herbs2000.com/herbs/herbs_pleurisy_root.htm
Forager Chef 'Foraging and Cooking Milkweed'. Available at: https://foragerchef.com/guide-to-milkweed/ Traditional / reference
https://foragerchef.com/guide-to-milkweed/
North Carolina Extension Gardener Plant Toolbox 'Apocynum cannabinum (Dogbane)'. Available at: https://plants.ces.ncsu.edu/plants/apocynum-cannabinum/ Traditional / reference
https://plants.ces.ncsu.edu/plants/apocynum-cannabinum/

Shara, M. and Stohs, S.J (2015) 'Efficacy and Safety of White Willow Bark (Salix alba) Extracts', Phytotherapy Research, 29(8), pp. 1112-1116. doi:10.1002/ptr.5377 Meta-analysis / review
https://doi.org/10.1002/ptr.5377
Maistro, E.L., Terrazzas, P.M., Perazzo, F.F., Gaivao, I.O.M. and others (2020) 'Salix alba (white willow) medicinal plant presents genotoxic effects in human cultured leukocytes', Journal of Toxicology and Environmental Health, Part A, 82(23-24), pp. 1223-1234. doi:10.1080/15287394.2019.1711476 Preclinical
https://doi.org/10.1080/15287394.2019.1711476
Matyjaszczyk, E. and Schumann, R. (EU-FORA) (2018) 'Risk assessment of white willow (Salix alba) in food', EFSA Journal, 16(Suppl 1), pp. e16081. doi:10.2903/j.efsa.2018.e16081 Meta-analysis / review
https://doi.org/10.2903/j.efsa.2018.e16081
Phillips, H.N., Sharpe, K.T., Endres, M.I. and Heins, B.J (2021) 'Effects of oral white willow bark (Salix alba) and intravenous flunixin meglumine on prostaglandin E2 in healthy dairy calves', JDS Communications, 3(1), pp. 49-54. doi:10.3168/jdsc.2021-0138 Preclinical
https://doi.org/10.3168/jdsc.2021-0138
Kong, C.S., Kim, K.H., Choi, J.S., Kim, J.E. and others (2014) 'Salicin, an extract from white willow bark, inhibits angiogenesis by blocking the ROS-ERK pathways', Phytotherapy Research, 28(8), pp. 1246-1251. doi:10.1002/ptr.5126 Preclinical
https://doi.org/10.1002/ptr.5126
Noleto-Dias, C., Ward, J.L., Bellisai, A., Lomax, C. and Beale, M.H (2018) 'Salicin-7-sulfate: A new salicinoid from willow and implications for herbal medicine', Fitoterapia, 127, pp. 166-172. doi:10.1016/j.fitote.2018.02.009 Preclinical
https://doi.org/10.1016/j.fitote.2018.02.009
Wolfle, U., Haarhaus, B., Kersten, A., Fiebich, B. and others (2015) 'Salicin from Willow Bark can Modulate Neurite Outgrowth in Human Neuroblastoma SH-SY5Y Cells', Phytotherapy Research, 29(10), pp. 1494-1500. doi:10.1002/ptr.5400 Preclinical
https://doi.org/10.1002/ptr.5400
Gagnier, J.J., van Tulder, M., Berman, B. and Bombardier, C (2006) 'Herbal medicine for low back pain (Cochrane review)', Cochrane Database of Systematic Reviews, (2), pp. CD004504. doi:10.1002/14651858.CD004504.pub3 Meta-analysis / review
https://doi.org/10.1002/14651858.CD004504.pub3
Oltean, H., Robbins, C., van Tulder, M.W., Berman, B.M. and others (2014) 'Herbal medicine for low-back pain (Cochrane review update)', Cochrane Database of Systematic Reviews, 2014(12), pp. CD004504. doi:10.1002/14651858.CD004504.pub4 Meta-analysis / review
https://doi.org/10.1002/14651858.CD004504.pub4
Amel Zabihi, N., Mahmoudabady, M., Soukhtanloo, M., Hayatdavoudi, P. and others (2018) 'Salix alba attenuated oxidative stress in the heart and kidney of hypercholesterolemic rabbits', Avicenna Journal of Phytomedicine, 8(1), pp. 63-72. Preclinical
https://scholar.google.com/scholar?q=Salix%20alba%20attenuated%20oxidative%20stress%20in%20the%20heart%20and%20kidney%20of%20hypercholesterolemic%20rabbits
Vlachojannis, J.E., Cameron, M. and Chrubasik, S (2009) 'A systematic review on the effectiveness of willow bark for musculoskeletal pain', Phytotherapy Research. doi:10.1002/ptr.2747 Meta-analysis / review
https://doi.org/10.1002/ptr.2747
European Medicines Agency (HMPC) (n.d.) 'European Union herbal monograph on Salix [various species], cortex (Salicis cortex)'. Available at: https://www.ema.europa.eu/en/medicines/herbal/salicis-cortex Traditional / reference
https://www.ema.europa.eu/en/medicines/herbal/salicis-cortex
Chrubasik, S., Eisenberg, E., Balan, E., Weinberger, T., Luzzati, R. and Conradt, C (2000) 'Treatment of low back pain exacerbations with willow bark extract: a randomized double-blind study', The American Journal of Medicine, 109(1), pp. 9--14. doi:10.1016/S0002-9343(00)00442-3 Randomized trial
https://doi.org/10.1016/S0002-9343(00)00442-3

Pleurisy Root monograph Willow Bark monograph Compare other plants

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.