Blessed thistle, also known as holy thistle, has been used since the Middle Ages to treat bubonic plague, promote digestive health and prevent infection. Today, blessed thistle is most commonly used to increase the production of breastmilk in nursing mothers. Blessed thistle is typically prepared as a tea using the tops, leaves, and upper stems or sold as a supplement in capsule, tincture, or powdered forms. In addition to promoting lactation, blessed thistle is believed to stimulate appetite and treat diarrhea, indigestion, colds, and flu. Others apply blessed thistle directly to boils, abscesses, and other skin infections to speed healing. Outside of its medicinal uses, blessed thistle is a key ingredient in the alcoholic liqueur Benedictine.
What Research Tells Us About Blessed Thistle
Blessed thistle is believed to stimulate lactation in nursing parents. It might be able to fight off bacterial infections in the body, and possibly even be an anti-carcinogen. More research will help confirm just how much this herb can really do. The use of blessed thistle in folk medicine has been handed down from one generation to the next. In most cases, there is little clinical evidence to support its use. Although bitter, the plant is edible and rich in a compound known as cnicin, which is believed to have anti-inflammatory, antibacterial, and anti-cancer properties. Here is what some of the current research says about blessed thistle:
Lactation
Alternative practitioners will commonly prescribe blessed thistle as a galactagogue, which is something you take to stimulate lactation. Although it is believed to increase the hormones prolactin (which boosts the milk supply) and oxytocin (which enables to release of milk from the nipples), there is nothing in the current body of medical literature to suggest this actually occurs. By contrast, milk thistle has been shown to be beneficial in promoting lactation in a number of smaller studies, including a 2008 trial from Italy in which the use of S. marianum increased breastmilk production in nursing mothers by 64.43% compared to 22.51% in the placebo group. Further research is needed to determine whether these same properties can be attributed to milk thistle.
Bacterial Infection
There is little evidence that blessed thistle can prevent or avert the course of the common cold, flu, or other viral infections. On the hand, research suggests that the herb may help neutralize certain common bacteria, including Staphylococcus aureus. While it is unknown how potent this effect is, particularly when taken by mouth, the results lend further credence to the use of blessed thistle as a topical antibacterial. The same effect may be extended to common fungal infection as well.
Cancer
Even less is known about cnicin’s purported anti-tumor properties. Most of the research is limited to tests tube studies, some of which have shown that cnicin is not toxic to Mycobacterium tuberculosis (TB) or breast cancer cells. Much more research would be needed to see if these same effects can occur outside of the test tube.
Possible Side Effects
Blessed thistle is considered safe when used as a tea. However, even in its tea form, it can cause stomach upset, nausea, and vomiting if consumed in excess. The same applies to blessed thistle supplements and tinctures. Blessed thistle should be avoided in people with inflammatory bowel diseases like Crohn’s disease and ulcerative colitis. Doing so can lead to a rebound or worsening of symptoms. Blessed thistle also exerts a mild diuretic effect and should be used with caution if you are taking a pharmaceutic diuretic (“water pill”) like Lasix (furosemide). Since blessed thistle can increase stomach acid, it may interfere with antacids and other heartburn medications (including proton pump inhibitors and H2 blockers). To be safe, take blessed thistle four hours before or four hours after an antacid dose. While blessed thistle is presumed to be safe for nursing mothers, it may stimulate uterine contractions and should be avoided during pregnancy. Do not use blessed thistle or any similar herbal product in children.
Dosage and Preparation
There are no guidelines directing the appropriate use of blessed thistle. Most supplements are offered in 300-milligram to 450-milligram formulations; thrice-daily doses are considered safe within this range. Doses over 5 grams (5,000 milligrams) per day are associated with an increased risk of side effects. Blessed thistle tea can be made by steeping 1 to 3 teaspoons of the dried herb in one cup of hot water for 10 minutes. Proponents believe that taking blessed thistle with fenugreek can further increase the production of breastmilk. Others will use it with alfalfa, stinging nettle, or goat’s rue. Some commercially prepared milk-boosting products (such as Traditional Medicinal’s Mother’s Milk Tea, Motherlove’s More Milk, and More Milk Plus) contain blessed thistle and other herb galactagogues.
What to Look For
Herbal remedies are not strictly regulated in the United States. Because of this, the quality can vary from one brand to the next. To ensure better quality and safety, stick with well-known supplements manufacturers with an established market presence. While many vitamin manufacturers will submit the products for voluntary inspection by the U.S. Pharmacopeia (USP), ConsumerLab, or other independent certifying bodies, herbal supplements manufacturers are less likely to do so. For an added layer of safety, choose supplements that have been certified organic under the regulations of the U.S. Department of Agriculture (USDA). Doing so can reduce your risk of exposure to pesticides, heavy metals, and other common contaminants.
Other Questions
How long does it take for blessed thistle to work?
Like all herbs, blessed thistle doesn’t work for everyone. However, some breastfeeding mothers report an increase in breast milk after using blessed thistle for only a few days. When fenugreek is also taken, blessed thistle appears to work even better. For the best results, breastfeed more often or pump after or between feedings. Blessed thistle is more likely to work when there is an increase in breast stimulation.
