Blessed thistle (Cnicus benedictus L.)
Background
Blessed thistle leaves, stems, and flowers have traditionally been used in "bitter" tonic drinks and in other preparations taken by mouth to enhance appetite and digestion. Blessed thistle may also be included in the unproven anti-cancer herbal remedy Essiac. This herb has been tested in laboratory studies for its properties against infections, cancer, and inflammation with promising results. However, high-quality trials showing benefits in humans are lacking.
Synonyms
Bitter thistle, cardin, Carbenia benedicta , Chardon Benit, Cardo Santo, Carduus benedictus, Cnici benedicti herba, cnicus, holy thistle, Kardo-benedictenkraut, St. Benedict thistle, salonitenolide, spotted thistle.
Note: Blessed thistle should not be mistaken for milk thistle ( Silybum marianus ) or other members of the thistle family.
Evidence
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
| Uses based on scientific evidence | Grade* |
| Bacterial infections Laboratory studies report that blessed thistle (and chemicals in blessed thistle such as cnicin and polyacetylene) has activity against several types of bacteria and no effects on some types. Reliable human study is lacking. Further evidence is necessary in this area before a firm conclusion can be drawn. | C |
| Indigestion and flatulence (gas) Blessed thistle is traditionally believed to stimulate stomach acid secretion, and has been used as a treatment for indigestion or gas. However, there is limited scientific study in these areas. Additional research is needed before a firm conclusion can be reached. | C |
| Viral infections Laboratory studies report no activity of blessed thistle against herpes viruses, influenza, or poliovirus. Effects of blessed thistle (or chemicals in blessed thistle called lignans) against HIV are not clear. Human research of blessed thistle as a treatment for viral infections is lacking. | C |
*Key to grades
A: Strong scientific evidence for this use;
B: Good scientific evidence for this use;
C: Unclear scientific evidence for this use;
D: Fair scientific evidence against this use;
F: Strong scientific evidence against this use.
Grading rationale
Uses based on tradition or theory
The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
Abortifacient, anorexia, appetite stimulant, astringent, bleeding, blood purifier, boils, breast milk stimulant, bubonic plague, cancer, cervical dysplasia, choleretic (bile flow stimulant), colds, contraceptive (birth control), diaphoretic (sweat stimulant), diarrhea, digestion enhancement, diuretic (increasing urine), expectorant, fever reducer, gallbladder disease, jaundice, liver disorders, inflammation, malaria, memory improvement, menstrual disorders, menstrual flow stimulant, painful menstruation, rabies, salivation stimulant, skin ulcers, wound healing, yeast infections.
Dosing
The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.
Adults (over 18 years old)
Tea, tinctures and liquid extracts are available. Traditional doses include 1.5 to 3 grams of dried blessed thistle flowering tops steeped in 150 milliliters of boiling water taken three times daily, or 1 to 3 teaspoons of dried blessed thistle herb in one cup of boiling water for 5 to 15 minutes taken three times daily (sometimes recommended to be used 30 minutes before meals). 1.5 to 10 milliliters of other preparations have been taken by mouth up to three times daily. May be bitter in taste.
Children (under 18 years old)
Not recommended due to lack of lack of reliable safety data.
Safety
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.
Allergies
Allergic reactions to blessed thistle including rash may occur, as well as cross-sensitivity to mugwort and echinacea. Cross-reactivity may also occur with bitter weed, blanket flower, chrysanthemum, coltsfoot, daisy, dandelion, dwarf sunflower, goldenrod, marigold, prairie sage, ragweed, or other plants in the Asteraceae/Compositae family.
