Blessed Thistle Benefits and Side Effects of Blessed Thistle

Blessed thistle contains the sesquiterpene lactones cnicin and salonitenolide. Cnin, a glycoside, is responsible for the herb’s bitterness, which stimulates the appetite and aids in digestion by encouraging the secretion of saliva and gastric juice. It may also act directly on the stomach and part of the small intestine.

Blessed thistle stimulates menstruation. It’s characterized as a bitter tonic, astringent, diaphoretic, antibacterial, expectorant, antidiarrheal, antihemorrhagic, vulnerary, antipyretic, and galactagogue. The antibacterial properties come from the volatile oil and the cnicin component. It’s available as capsules, decoction, dried herb, fluid extract, infusion, oil, tea, and tincture. The extract is a constituent in skin lotions, creams, and salves.

Benefits And Uses of Blessed ThistleBlessed Thistle

Blessed thistle is used orally to treat digestive problems such as liver and gallbladder diseases, loss of appetite, indigestion and heartburn, constipation, colic, diarrhea, dyspepsia, and flatulence. It may also improve memory, relieve menstrual complaints, control amenorrhea, regulate the menstrual cycle, increase perspiration, lower fever, enhance lactation, dissolve blood clots, control bleeding, and reduce rheumatic pain. It’s also used as an expectorant and antibiotic.

Topically, blessed thistle poultice is used for furuncles, wounds, ulcers, and hemorrhage. Blessed thistle is added to alcoholic beverages during manufacturing as flavoring.


  • Capsules: 2 capsules by mouth three times a day .
  • Decoction: 1 cup by mouth 30 minutes before meals; prepared by adding 1.5 to 2 g of finely chopped herb to 1 cup of water .
  • Liquid extract: (1:1 in 25% alcohol) 1.5 to 3 ml by mouth, three times a day. Mean daily dose: 4 to 6 g of herb or equivalent preparations .
  • Tea: 3 cups by mouth every day; prepared by adding 2 g of dried herb to 1 cup of boiling water and steeping for 10 to 15 minutes .
  • Tincture: 1 to 2 ml by mouth three times a day.

Side Effects of Blessed Thistle

Adverse effects reportedly associated with blessed thistle include nausea, vomiting, diarrhea, and contact dermatitis.

Because blessed thistle increases stomach acidity, it may interact with antacids, Hz antagonists, proton pump inhibitors, and sucralfate. Possible worsening of hypoglycemia may occur when blessed thistle is used with insulin and oral antidiabetics. Blessed thistle may potentiate the antibiotic activity of echinacea. There may be cross sensitivity with other herbs from the Compositae family such as mugwort and cornflower.

Pregnant and breast-feeding patients should avoid using blessed thistle because it may promote menstruation. Those with acute stomach inflammation, ulcers, or hyperacidity, should avoid using blessed thistle because it stimulates gastric juices. Those with a history of contact dermatitis, especially in relation to other members of the Compositae family including ragweed, chrysanthemums, marigolds, and daisies and those with diabetes, ulcers, acute stomach inflammation, and hyperacidity of the GI tract should used blessed thistle with caution.

Clinical considerations

  • infusion of more than 5g per cup of tea may cause vomiting and stomach irritation.
  • Blessed thistle may cross-react with mugwort and cornflower.
  • If patient has diabetes, monitor his blood glucose level. Warn patient not to delay seeking appropriate medical evaluation for indigestion, anorexia, or heartburn because doing so may delay diagnosis of a potentially senous medical condition.
  • If patient is pregnant or breast-feeding, advise her not to use blessed thistle.
  • If patient is taking a drug for diabetes, ulcers, or heartburn, instruct him to contact his health care provider before taking blessed thistle because his drug dosage may need to be adjusted.
  • If patient is collecting blessed thistle himself, advise him to wear protective clothes and glasses because the plant can cause inflammation of the skin, eyes, and mucous membranes.
  • Advise patient not to add milk or cream to blessed thistle tea; doing so may mute the gastric acid secretion.
  • Tell patient to remind prescriber and pharmacist of any herbal or dietary supplement that he’s taking when obtaining a new prescription.
  • Advise patient to consult his health care provider before using an herbal preparation because a treatment with proven efficacy may be available.
Research summary

The concepts behind the use of blessed thistle and the claims made regarding its effects have not yet been validated scientifically.