Medicinal Plants by Infusion: what the science really shows, and what it does not show
Plant-derived active substances are biologically active and clinically relevant. But it depends on which substance, which dosage form and which evidence base.
Nature has a pharmacy. But we have to be honest.
Almost a third of all modern medications are originally based on plant substances. Aspirin comes from willow bark. Morphine from the poppy. Taxol from the yew tree. Artemisinin against malaria from Artemisia annua. These substances act, strongly, measurably, sometimes life-savingly.
That means: plant medicine is no esoterics. Biologically active substances from plants can act at the cellular level. Studies document this. For some applications, very well.
But it also means something I want to tell you directly: the active substance, the dosage form and the route of administration decide everything. A study on oral chamomile tea is no evidence for a chamomile infusion into the bloodstream. That sounds self-evident. But it is a difference that regularly blurs in the literature on plant infusions.
In this article I will show you what the science really shows, with the plant substances we use in integrative medicine. Honestly. With correct studies. With clear limits.
The three evidence levels in plant infusion therapy
Before we discuss individual substances: it helps to distinguish three evidence levels. They are often mixed up in the popular literature.
1. Milk thistle (Silybum marianum): the best-documented active substance for IV
Silibinin, the active substance with real IV evidence
IV: strong evidence Liver, detoxification, cell protectionMilk thistle is the plant for which I can say most directly: intravenous administration is clinically established, for certain indications. The active substance silibinin (the main component of silymarin) has two confirmed IV applications that go beyond case reports.
Ferenci and colleagues tested in 2008 in an RCT in 36 patients with therapy-resistant hepatitis C who had not responded to interferon. IV silibinin (Legalon SIL) in doses up to 20 mg/kg/day led to a dose-dependent HCV-RNA reduction of up to 3.02 log₁₀, a real antiviral effect that no oral formulation achieves.
Ferenci P et al. Silibinin is a potent antiviral agent in patients with chronic hepatitis C not responding to pegylated interferon/ribavirin therapy. Gastroenterology. 2008;135(5):1561–1567. DOI: 10.1053/j.gastro.2008.07.072The most important life-saving application: IV silibinin (Legalon SIL) is a recognized treatment for death-cap mushroom poisoning (Amanita phalloides). The mechanism is clear: silibinin blocks the uptake transporter OATP1B3, through which alpha-amanitin enters liver cells.
Hruby K et al. Pharmacotherapy of Amanita phalloides poisoning. Wien Med Wochenschr. 1983. Saller R et al., several retrospective reportsFried MW et al. 2012 in JAMA (DOI: 10.1001/jama.2012.8265, n=154) tested oral silymarin in hepatitis C patients, and found no significant benefit. This study documents: orally administered silymarin achieves no clinically relevant effect in HCV. That is why the difference between IV and oral matters so much for this substance.
For daily practice: oral milk thistle (silymarin) shows in a meta-analysis of 55 RCTs (n=3,545) significant AST and ALT reductions in NAFLD and viral hepatitis. For liver support, metabolic support and oxidative protection, the oral form is well documented.
2. Artichoke (Cynara scolymus): good for liver and lipid metabolism, but no IV candidate
Artichoke extract, oral evidence, no IV benefit documented
Oral: moderate evidence IV: no studiesArtichoke extract is one of the best-studied liver plants in phytotherapy. Its bitter compounds (cynarin, luteolin) stimulate bile secretion, improve hepatic lipid metabolism and protect liver cells from oxidative stress.
Liu and colleagues analyzed in 2024 37 RCTs with 2,509 patients on natural substances and liver enzymes in NAFLD. Artichoke extract took first place for AST reduction (SUCRA 99.1 percent) among seven compared plant extracts.
Liu X et al. Network meta-analysis of natural products for liver enzymes in NAFLD. Phytother Res. 2024. DOI: 10.1002/ptr.8182Sahebkar et al. analyzed 9 RCTs with 702 patients. Total cholesterol fell by about 17.6 mg/dL (about 6 to 7 percent), LDL by about 14.9 mg/dL (about 8 to 11 percent). Moderate, statistically significant effects, but no dramatic reductions.
Sahebkar A et al. Effects of artichoke leaf extract on lipid profiles. Crit Rev Food Sci Nutr. 2018;58(15):2549–2556. DOI: 10.1080/10408398.2017.1332572For practice: oral artichoke extract is well justified in hepatic steatosis, elevated liver values and dyspeptic complaints. Intravenous artichoke has not been investigated in any controlled study.
3. Ginkgo biloba (EGb 761): strong mechanisms, mixed study data
EGb 761, anchored in German guidelines, IV form barely available
Oral: moderate evidence IV: historical, no longer standardGinkgo biloba is the most-studied plant active substance in neurology. The standardized extract EGb 761 improves cerebral microcirculation, inhibits platelet activating factor (PAF) and has neuroprotective properties.
The German S3 Dementia Guideline contains EGb 761 (Tebonin) with a "may" recommendation for mild to moderate Alzheimer's dementia and vascular dementia, the only phytopharmaceutical at all. The oral daily dose is 240 mg of EGb 761.
S3 Dementia Guideline. DGPPN/DGN. 2016. EGb 761 "may" recommendation for mild to moderate dementia.Sereda and colleagues analyzed 12 studies with 1,915 participants. EGb 761 showed no significant difference from placebo in tinnitus. For this indication, ginkgo should not be recommended.
Sereda M et al. Ginkgo biloba for tinnitus. Cochrane Database Syst Rev. 2022;(7):CD013514. DOI: 10.1002/14651858.CD013514.pub2On the IV form: the German IV formulation (Tebonin injekt) is no longer in regular distribution. In China, ginkgo injections are used in stroke, but the study quality is overall weak.
4. Curcumin (turmeric): a real anti-inflammatory, with important limitations
Curcumin, modest but real oral effects, critical IV safety questions
Oral: moderate evidence IV: only investigational, safety concernsCurcumin is biologically active as an anti-inflammatory, this is very well documented through in-vitro data and preclinical studies. It inhibits NF-kappaB, modulates cytokines and has antioxidant properties.
Dehzad and colleagues analyzed 35 RCTs in 2024. Systolic blood pressure fell by −2.02 mmHg (95 percent CI −2.85 to −1.18), diastolic by −0.82 mmHg. Statistically significant, but clinically modest, a 5 mmHg reduction is considered the clinical threshold.
Dehzad F et al. Curcumin supplementation improves blood pressure and endothelial function. Clin Nutr ESPEN. 2024 Feb;59:347–358. DOI: 10.1016/j.clnesp.2023.12.009What works for curcumin? Oral, highly bioavailable formulations (liposomal, micellar, with piperine) achieve higher plasma levels. For inflammatory states and metabolic syndrome, oral curcumin is a sensible adjunct.
5. Polyphenols, resveratrol, EGCG: interesting basic research, weak clinical data
Resveratrol & EGCG, biochemically fascinating, clinically not robust
Oral: weak evidence IV: no studiesResveratrol activates sirtuins (longevity genes), EGCG from green tea inhibits inflammatory pathways, in vitro and in animal models impressively. In humans the effects are more modest.
Lorenz and colleagues conducted an RCT in 50 subjects: green tea significantly improved flow-mediated vasodilation, but isolated EGCG at the same dose did not. High-dose EGCG (more than 800 mg per day) is moreover associated with hepatotoxicity.
Lorenz M et al. Green tea and EGCG: vascular effects. Sci Rep. 2017. DOI: 10.1038/s41598-017-02384-xNo clinical study has investigated IV polyphenols for cardiovascular endpoints. Polyphenol-rich nutrition has consistent epidemiological associations with vascular health, but the mechanisms are probably more complex than the isolated single substance via infusion.
6. Chamomile, lemon balm, peppermint: effective plants, wrongly classified
Calming herbs, well-documented orally, but never investigated as IV
Oral / tea: moderate evidence IV: nonexistentHere clarity is especially important: the German word "Infusion" means both "herbal tea" and "intravenous infusion". These are two completely different medical realities.
All clinical studies on chamomile, lemon balm and peppermint use oral application. There is not a single published clinical study on intravenous administration of these herbs in humans. For peppermint oil there is a case report of acute lung injury after intravenous injection. Oral evidence may not be extrapolated to IV therapy.
Oral evidence, what studies show
- Peppermint oil (enteric-coated, oral): the strongest evidence in this group. Meta-analysis (9 RCTs, n=726): RR 2.23 for global symptom improvement in IBS.
- Chamomile (oral): SMD −0.73 for sleep quality in a meta-analysis (12 RCTs). No significant effect on insomnia severity.
- Lemon balm (oral): reduction of oxidative stress in small RCTs. Anxiolytic effects with high-dose extract.
- Spearmint vs. peppermint: anti-androgenic effects (relevant in PCOS) apply to spearmint (Mentha spicata), not to peppermint (Mentha piperita).
7. What this means for practice: my approach at Vivecura
My work in integrative medicine combines phytotherapy with orthomolecular medicine, biologically active plant substances combined with micronutrients like vitamin C, glutathione, magnesium or targeted amino acids.
Markus, 47, management consultant from Berlin-Mitte. He came with persistent exhaustion after COVID, elevated liver enzymes (ALT 62 U/L) and brain fog for seven months. Strategy: oral silymarin extract (600 mg per day), oral EGb 761 (240 mg per day) for microcirculation and cognition, combined with vitamin C and glutathione intravenously, sleep optimization and dietary adjustment. After eight weeks: ALT normalized (34 U/L), subjective cognitive improvement, sleep quality improved.
"Not every plant belongs in an infusion. But some do, and then with clear justification, not from tradition."
For intravenous use I deploy specifically what is evidence-based for it: IV vitamin C, IV glutathione (with an honest note about limited clinical data) and IV silibinin in specific liver indications. The classical herbs, milk thistle, artichoke, ginkgo, I use predominantly orally, where the evidence is strongest.
8. Overview: what the evidence really shows
| Active substance | Best evidence | IV status | Clinical relevance |
|---|---|---|---|
| Silibinin (milk thistle) | Oral (NAFLD, hepatitis), IV (HCV, Amanita poisoning) | IV: established (specific indications) | High in liver disease |
| Artichoke extract | Oral (NAFLD, cholesterol, dyspepsia) | IV: no studies | Good orally, no IV route |
| Ginkgo EGb 761 | Oral (mild dementia, guideline "may") | IV: historical, barely available | Moderate for cognition orally |
| Curcumin | Oral (blood pressure −2 mmHg, inflammation) | IV: investigational, fatality known | Low to moderate orally |
| Resveratrol | Oral (blood pressure −2 to 5 mmHg) | IV: no studies | Low orally |
| EGCG (green tea) | Oral (questionable whether EGCG is active) | IV: no studies | Unclear, hepatotoxicity high |
| Peppermint oil | Oral (IBS: 9 RCTs, strong evidence) | IV: case report acute lung injury | High orally, never IV |
| Chamomile | Oral (sleep: moderate evidence) | IV: no studies | Low to moderate orally |
| Lemon balm | Oral (anxiety, oxidative stress) | IV: no studies | Low orally |
9. An honest closing word on plant medicine
Plants act. That is no question. Aspirin, morphine, digitalis, quinine, the history of medicine is the history of substances that were first found in plants and then understood.
But not every plant belongs in a vein. And an herbal tea does not become something different by being renamed "infusion therapy". This honesty protects patients, and in the long term strengthens trust in the real possibilities of integrative medicine.
What I experience daily in my practice: plant active substances, orthomolecular micronutrients and an individualized diagnostic approach can produce real changes, when they are justified, combined and accompanied. That is the craft of integrative medicine.
Sources
- Ferenci P et al. Silibinin is a potent antiviral agent in patients with chronic hepatitis C not responding to pegylated interferon/ribavirin therapy. Gastroenterology. 2008;135(5):1561–1567. DOI: 10.1053/j.gastro.2008.07.072
- Fried MW et al. Effect of silymarin (milk thistle) on liver disease in patients with chronic hepatitis C unsuccessfully treated with interferon therapy. JAMA. 2012;308(3):274–282. DOI: 10.1001/jama.2012.8265
- Shahsavari F et al. Efficacy of silymarin supplementation on liver function tests: Umbrella meta-analysis of 55 RCTs. BMC Complement Med Ther. 2025. DOI: 10.1186/s12906-025-04886-y
- Liu X et al. Network meta-analysis of natural compounds for liver enzyme reduction in NAFLD. Phytother Res. 2024. DOI: 10.1002/ptr.8182
- Sahebkar A et al. Effects of artichoke leaf extract on lipid profiles: A systematic review and meta-analysis. Crit Rev Food Sci Nutr. 2018;58(15):2549–2556. DOI: 10.1080/10408398.2017.1332572
- Sereda M et al. Ginkgo biloba for tinnitus. Cochrane Database Syst Rev. 2022;(7):CD013514. DOI: 10.1002/14651858.CD013514.pub2
- Dehzad F et al. Curcumin supplementation improves blood pressure and endothelial function. Clin Nutr ESPEN. 2024 Feb;59:347–358. DOI: 10.1016/j.clnesp.2023.12.009
- US FDA. Investigates two serious adverse events associated with ImprimisRx's compounded curcumin emulsion product for injection. 2017. fda.gov
- Lorenz M et al. Green tea and EGCG: vascular effects. Sci Rep. 2017. DOI: 10.1038/s41598-017-02384-x
- Khanna R et al. Peppermint oil for IBS. J Clin Gastroenterol. 2014;48(6):505–512. DOI: 10.1097/MCG.0b013e3182a88357
- Hieu TH et al. Chamomile for sleep: systematic review and meta-analysis. Phytother Res. 2019;33(6):1604–1615. DOI: 10.1002/ptr.6349
- Hauser RA et al. Randomized trial of intravenous glutathione in Parkinson's disease. Mov Disord. 2009;24(7):979–983. DOI: 10.1002/mds.22401
- S3 Dementia Guideline. DGPPN/DGN. 2016.