Aug 17, 2004: Are Fenugreek and Milk-Thistle safe for lactating mothers?

Recently an infant had a “spell” about 45 minutes after breast feeding.  Mom was taking milk thistle and fenugreek as recommended by a midwife who was caring for her.  The infant’s work-up was negative.  Could either of these herbs have played a role?

Milk thistle (also known as “Holy thistle”, “Lady’s thistle”, “and Mary thistle”) was once grown in Europe. The de-spined leaves were used in salad and cooked as a green; the stalks, roots, and flowers were also eaten. Various preparations of milk thistle have been used medicinally for over 2000 years. In homeopathy, a tincture of the seeds has been used to treat various liver disorders, jaundice, bronchitis, and varicose veins.  

Milk thistle is used as a hepatoprotectant and antioxidant.  Silymarin, the primary component, alters the outer liver cell membrane to block toxin binding sites, scavenges prooxidant free radicals, increases intracellular concentration of glutathione, and inhibits peroxidizing enzymes.

Data is scanty.  However, this herb has been extensively administered without demonstrating any toxicity.  Information regarding pregnancy and lactation is lacking, but I doubt that this herb caused the “spell”.

Fenugreek (also known as “Hilba”) is grown in southern Europe, Asia, and North Africa.  This herb has been used for the treatment of boils, diabetes, cellulites and tuberculosis.  It contains 50% mucilage and the alkaloid Trigonelline in the seed.

Fenugreek has been shown to lower blood glucose levels in dogs.  Fenugreek extracts have demonstrated anti-inflammatory and diuretic activity in animal models.  The extracts also have oxytoxic activity.

Due to the oxytoxic and hypoglycemic action of this herb, most sources recommend that fenugreek not be administered during pregnancy and lactation.  

The hypoglycemic action of fenugreek may have been the culprit in this “spell”.  This case also emphasizes the need to ask about “natural” or “herbal remedies”-including ones recommended by health care providers.

Thanks to Dr. Keowan for the question.  

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Donna Seger, M.D
Medical Director
Tennessee Poison Center