Milk thistle, known scientifically as Silybum marianum, is an herb that has been used for centuries as an aid to treat ailments associated with the liver and gallbladder, and it is still commonly used as a supplement to promote liver health. The National Center For Complementary And Alternative Medicine says milk thistle produces few adverse reactions in those who take it, but there are some risks associated with its use.
Interaction With Medications
Milk thistle works to protect the liver by inhibiting liver enzyme activity. It can slow down or reduce the activity of enzymes in the liver, according to a report from researchers at the University of Pittsburgh. These enzymes also break down substances that are ingested, including food and medications. If you are taking milk thistle and are on medication, the liver enzymes are not working as quickly, which means the medication may stay in the bloodstream longer than it should. The report, published in the Nov. 1, 2000, issue of "Drug Metabolism and Distribution," concludes that even small amounts of milk thistle can raise the risk of side effects from medication, as well as interfere with how well medication works.
Some medications also are broken down by the same enzymes as milk thistle, and if the liver enzymes are busy with the milk thistle, they aren't able to break down the medications effectively. The University of Maryland Medical Center lists some of these medications as allergy drugs, blood thinners such as warfarin, statin drugs for cholesterol, anxiety drugs such as diazepam and some cancer medications.
Intestinal Upset
One of the few side effects reported for milk thistle is an upset stomach. The National Cancer Institute notes that taking milk thistle may cause heartburn, upset stomach, diarrhea and nausea. This effect is attributed to the active component in milk thistle, which is silymarin. These effects are usually seen in those taking high doses, such as 1500 milligrams or more a day.
Allergic Reaction
Even though milk thistle is usually consumed as capsules or tablets, the fact that it is derived from an herbal plant source means it can cause an allergic reaction in those who have allergies to other plants from the same plant family. If you are allergic to ragweed, daisies, marigolds or chrysanthemums, the National Center for Complementary and Alternative Medicine says you may be at higher risk for a reaction to milk thistle and should avoid it. If you take milk thistle and experience a skin rash, swollen tongue or lips, throat constriction or difficulty breathing, you should discontinue use and get immediate medical attention.
References
- National Center For Complementary And Alternative Medicine: Milk Thistle
- Drug Metabolism and Disposition: Milk Thistle, a Herbal Supplement, Decreases the Activity of CYP3A4
- University of Maryland Medical Center: Milk Thistle
- National Cancer Institute: Milk Thistle
- Zhion: Research Notes: Milk Thistle Benefits and Side Effects
Member Comments