Prim. ao Univ. Prof. Dr. Christian Lampl



As a clinically active orthodox medical practitioner, I am often asked whether natural products could have a positive effect, especially on the immune system in the case of various diseases. In order to answer this question conclusively, clinical studies would be necessary. However, in the case of plant-based natural products, such studies are very difficult or costly to carry out, or in some cases have already been carried out. However, this question can be answered by getting to the bottom of the content of the natural products.

The following excerpt is based exclusively on scientific studies and their results.

For example, the ingredient of the liquorice root is glycyrrhizinic acid. This not only has an expectorant effect, but is also believed to have an effect against bacteria and fungi (1). According to a study by the Frankfurt Virological Institute (2) published in one of the most renowned medical journals "The Lancet", glycyrrhizinic acid, proven in the laboratory, should prevent the penetration of SARS viruses into our cells. There are also the first laboratory chemical indications that preparations made from liquorice are effective against herpes viruses (3). However, please only use liquorice roots in consultation with your doctor, as the ingredients affect the body's own hormones (such as cortisol and aldosterone). As a result, blood pressure can rise and the blood sugar level can be adversely affected. Therefore, those who already suffer from high blood pressure, diabetes or kidney problems should not use liquorice as a mono-product. This also applies during pregnancy.

Science also dealt with the black and red currant. It has been shown in animal studies that these berries have anti-inflammatory and antioxidant properties (4,5). Antioxidants have a great physiological importance. They inactivate reactive oxygen species in the organism, the excessive presence of which leads to oxidative stress, which in turn is associated with ageing and the development of a number of diseases. Small, i.e. physiological, quantities promote the stress resistance capacity, health and life expectancy of the human being.


A similar approach should be adopted for the Cat's Claw (Uncaria tomentosa) apply. Clinical scientific studies have found positive, pain-relieving effects against rheumatoid arthritis (6,7). In addition, they are said to have a blood pressure-lowering effect.


The Nettles are a genus of the stinging nettle family (Urticaceae). A distinction is made between large nettles (Urtica dioica L.) and small nettles (Urtica urens L.). Stinging nettles contain iron, vitamins (A, B, C, E), calcium, potassium, magnesium, silicic acid, trace elements, chlorophyll, carotene diode and flavonoids (9). The stinging hairs contain acetylcholine, histamine, serotonin, formic, butter and acetic acid. Scientific studies are not very numerous, but flushing is evident in inflammatory diseases of the urinary tract (9). Supporting treatment of rheumatic complaints is also being discussed. Of interest are laboratory experiments in which nettle extracts can induce the cell death of tumour cells (prostate carcinoma cells) (10). Other studies are investigating the extent to which nettle extracts can be used in breast cancer (11).


The Dandelion plant (Taraxacum officinale) is also a very interesting substance for science. In addition to the bitter substances, it also contains caratinoids, vitamins (B, C, E), potassium, calcium, iron and omega-3 fatty acids. Dandelion is said to have a purifying effect and to support the liver in breaking down toxins. Italian scientists (12) confirmed the positive effect of these plants on the liver and gall bladder.

There has also been a questionable anti-cancer, antioxidant and protective effects of medicinal plants studied. While turmeric showed the strongest antioxidant effect, dandelion also showed a strong antioxidant effect. Other researchers reported that a dietary supplement containing dandelion, among other things, could inhibit the growth of prostate cancer cells (13). In a small study by Clare and collaborators (14), the administration of 8 ml of dandelion leaf extract three times a day resulted in a significant increase in urine frequency and quantity, which demonstrated the diuretic effect.


The Lemon balm (Melissa officinalis) is especially known for its calming effect, which is why it can be helpful for sleep disorders, nervousness and restlessness (15,16). This is made possible because certain ingredients of the plant act on a messenger substance which science calls a "GABA transmitter" (17). This messenger substance is, among other things, released in increased quantities, especially during chronic stress.


Another positive health effect could be the Olive leaf (Olea europea) It is not only said to have a positive effect against high blood pressure (grade I) (18), but also to have antiviral and antibacterial effects (19). However, there is a lack of reliable studies on humans.


The Grey Hair Cistrosis (Cistus incanus) is said to have an antiviral activity due to its high polyphenol content, in addition to an antioxidative protective effect (20). In 2009, a prospective, i.e. predictive, clinical placebo-controlled study with cistrosis was conducted at the renowned Charité University in Berlin (21). Patients with a cold (upper respiratory tract infections) received a cistus extract. Cold symptoms and also the inflammation marker CRP decreased significantly in the cistrosis group, while there was a barely noticeable improvement in the placebo group.


In summary, there is clear scientific evidence that "medicinal plants" can have an often amazing and positive effect on certain diseases. They should generally be taken preventively and ultimately always in accordance with evidence-based medicine (scientifically proven by clinical studies). If one refers to pharmacological data, clinical studies and empirical knowledge, a profile can be identified that shows the importance of medicinal plants. Studies have been conducted worldwide to test the effectiveness of medicinal plants. To date, more than 10,000 of them have been scientifically investigated. Most medicinal plants are generally harmless in the recommended dosage, even if side effects do sometimes occur. Some can cause allergies. Medicinal plants contain many substances, known and unknown. The effect is probably due to the interaction of the individual substances, which influence each other - both in strength and over time. It is also important to inform your doctor of your "herbal medicinal products".




  1. Hosseinzadeh H, Nassiri-Asl M. Pharmacological effects of Glycyrrhiza and its bioactive constituents: update and review. Phytother Res 2015;29:1868-86
  2. Cinatl J et al, Glycyrrhizin, an active component of liquorice roots, and replication of SARS-associated coronavirus Lancet. 2003 Jun 14;361(9374):2045-6
  3. Hirabayashi K et al, Antiviral activities of glycyrrhizin and its modified compounds against human immunodeficiency virus type 1 (HIV-1) and herpes simplex virus type 1 (HSV-1) in vitro. Chem Pharm Bull (Tokyo). 1991Jan;39(1):112-5.
  4. Tabart J. et al. Antioxidant and anti-inflammatory activities of Ribes nigrumFoodChem. 2012;131:1116-1122.
  5. Staszowska-Karkut M and Materska M. Phenolic Composition, Mineral Content, and Beneficial Bioactivities of Leaf Extracts from Black Currant(Ribes nigrum ), Raspberry(Rubus idaeus), and Aronia(Aronia melanocarpa). Nutrients 2020, 12, 463;
  6. Mur, E. et al Randomized double blind trial of an extract from the pentacyclic alkaloid-chemotype of uncaria tomentosa for the treatment of rheumatoid arthritis. The Journal of Rheumathology, 2002, 29(4):678-81
  7. Piscoya, J., et al. Efficacy and safety of freeze-dried cat's claw in osteoarthritis of the knee: mechanisms of action of the species Uncaria guianensis. Inflammation Research, 2002; 50(9):442-8.
  8. Tabassum, N. & Ahmad, F. Role of natural herbs in the treatment of hypertension Pharmacognosy Review, 2011 5(9): 30-40.
  9. Barnes J, Anderson LA, Phillipson JD. Herbal Medicines. London: Pharmaceutical Press, 2002
  10. Levy, A. et al (2014): Urtica Dioica Induces Cytotoxicity in Human Prostate Carcinoma LNCaP Cells: Involvement of Oxidative Stress, Mitochondrial Depolarization and Apoptosis. In: Tropical Journal of Pharmaceutical Research, Vol. 13, No. 5, pp. 711-717.
  11. Fattahi, S. et al (2013): Antioxidant and Apoptotic Effects of an Aqueous Extract of Urtica dioica on the MCF-7 Human Breast Cancer Cell Line. In: Asian Pacific Journal of Cancer Prevention, Vol. 14, pp. 5317-5232
  12. Menghini L et al, Antiproliferative, protective and antioxidant effects of artichoke, dandelion, turmeric and rosemary extracts and their formulation, Int J Immunopathol Pharmacol. 2010 Apr-Jun;23(2):601-10
  13. Jiang J et al, Suppression of growth and invasive behavior of human prostate cancer cells by ProstaCaid: mechanism of activity, Int J Oncol. 2011 Jun;38(6):1675-82
  14. Clare BA et al, The diuretic effect in human subjects of an extract of Taraxacum officinale folium over a single day, Journal of Alternative and Complementary Medicine, 2009 Aug;15(8):929-34
  15. European Medicines Agency (2013): Assessment report on Melissa officinalis L., folium, EMA/HMPC/196746/2012
  16. Soltanpour, A. et al (2019): Effects of Melissa officinalis on anxiety and sleep quality in patients undergoing coronary artery bypass surgery: A double-blind randomized placebo controlled trial. European Journal of Integrative Medicine, Vol. 28, pp. 27-37
  17. Scaglione, F. and Zangara, A. (2017): Valeriana Officinalis and Melissa Officinalis Extracts Normalize Brain Levels of GABA and Glutamate Altered by Chronic Stress. In: Journal of Sleep Disorders and Management, Vol. 3, pp. 1-7,
  18. El Sedef, N., and Sibel Karakaya. "Olive tree (Olea europaea) leaves: potential beneficial effects on human health." Nutrition reviews 67.11 (2009): 632-638.
  19. Omar SH. "Oleuropein in olive and its pharmacological effects." Sci Pharm. 2010;78(2):133-54
  20. Attaguile G et al, Antioxidant activity and protective effect on DNA cleavage of extracts from Cistus incanus L. and Cistus monspeliensis L., Cell Biology and Toxicology, 2000;16(2):83-90
  21. Kalus U et al, Cistus incanus (CYSTUS052) for treating patients with infection of the upper respiratory tract. A prospective, randomized, placebo-controlled clinical study. Antiviral Res. 2009 Dec;84(3):267-71