Is Milk Thistle Tea Safe During Pregnancy?

No, milk thistle tea cannot be considered proven safe during pregnancy because its active plant compounds have not been adequately studied for their effects on the pregnant person or developing baby.

What is the short answer?

Avoid milk thistle tea during pregnancy unless your obstetrician, midwife or other pregnancy clinician advises you to use it. The concern is uncertainty: there is not enough research on the tea to establish its safety, rather than clear proof that a cup will cause harm.

Milk thistle contains compounds collectively known as silymarin. Most of the available research concerns extracts or individual compounds, not a brewed cup of milk thistle tea, so the findings do not establish a safe way to drink the tea during pregnancy.

If you have already had some, do not assume you have harmed your baby. Stop drinking it for now and tell your pregnancy clinician what you had; they can advise you based on your circumstances.

Why is milk thistle tea’s safety uncertain during pregnancy?

The main reason for caution is the lack of reliable pregnancy-specific evidence. Researchers have not established how much of milk thistle’s active compounds enters a particular cup of tea, or what exposure to those compounds means for pregnancy outcomes.

A 2019 review of silymarin safety reported that one pregnancy trial found no anomalies, but its authors still called for caution and more human research. That limited finding is not enough to prove that milk thistle tea is safe throughout pregnancy. An extract studied in a trial is also not necessarily equivalent to a tea made with a different product or brewing method.

A laboratory study using blood cells from pregnant women examined silibinin, a component of silymarin, in relation to inflammatory activity. The researchers did not test milk thistle tea as a pregnancy treatment or establish that drinking it is safe. Results from cells in a laboratory cannot show how the tea affects a pregnant person or fetus.

Milk thistle is sometimes marketed for liver support, but that is not a reason to use it during pregnancy. The liver and kidneys do most of the body’s detoxification, and milk thistle tea has not been shown to improve that process during pregnancy.

How much milk thistle tea is safe during pregnancy?

No pregnancy-safe amount has been established for milk thistle tea. There is no evidence-based number of cups, brewing strength or frequency that can be recommended as safe. A product being sold as a tea, rather than as a supplement, does not establish that it is safe during pregnancy.

Products can differ in their ingredients and concentration. Labels may also describe blends rather than milk thistle alone, making it important to check the full ingredient list. A label saying “natural” or “organic” does not establish pregnancy safety.

If your pregnancy clinician recommends a particular product, follow their individual advice rather than using a general amount found online. Tell them about any other herbal products or supplements you take so they can assess the whole picture.

When should you talk to a doctor or midwife?

Speak with your pregnancy clinician before using milk thistle tea, especially if you have a liver condition, diabetes, allergies to plants in the daisy family, or take prescription medicines. The silymarin safety review advises caution with medicines where small changes in drug levels can matter. Do not stop or change prescribed medication without advice from its prescriber.

If you drank milk thistle tea before learning about the uncertainty, contact your clinician for individual guidance. Keep the package or take a photo of the ingredients, and note when and approximately how much you drank. This information can help your clinician assess the exposure, particularly if the product contained other herbs or you developed symptoms.

Do not use milk thistle tea to manage suspected pregnancy complications or delay an assessment. Contact your pregnancy care team promptly for severe itching, especially of the palms or soles, or for a severe headache, vision changes or pain in the upper right abdomen. These symptoms can have several causes and need medical assessment.

Seek emergency care for trouble breathing, swelling of the tongue or throat, or fainting after drinking the tea. A serious allergic reaction needs immediate attention, regardless of whether milk thistle was the cause.