What Is Milk Thistle?

Milk thistle (Silybum marianum) is a tall, purple flowering plant with prickly spines. Originally from the Mediterranean region, milk thistle has a long history of use in medicine and healing. For centuries, this plant has been used to treat health problems of the liver and gallbladder. It’s also a well-known galactagogue (something that promotes breast milk production) that breastfeeding mothers take to help increase their supply of breast milk.

Milk Thistle for Breastfeeding

Milk thistle has been linked to breastfeeding for a very long time. Also known as Saint Mary’s Thistle and Our Lady’s thistle, this herb is a plant that has white veins running through its leaves. To some, these white veins symbolize breast milk, and it’s believed that when a breastfeeding mother uses this herb, it will lead to an increase in their breast milk supply. While research is limited, some studies do show that it boosts breast milk production when taken daily in the first weeks after delivery. Other studies show mixed results or no difference in milk production compared with those taking a placebo. Anecdotally, milk thistle has been used with positive results by breastfeeding mothers in India and Europe for generations. And, while there is only limited scientific evidence that milk thistle can help a nursing mother to make more breast milk, it has been shown to increase milk production in dairy cows. It is believed that the plant estrogens found in milk thistle could be one of the reasons some women report making more breast milk when they take this herb.

Milk Thistle Safety

Dietary supplements like milk thistle do not go through the same rigorous testing that medications do, however the limited research available shows minimal side effects and safety concerns.

Side Effects and Allergic Reactions

Milk thistle is generally considered to be a safe herb. The most common side effects are mild and stomach-related. When it’s taken in excessive amounts, loose bowel movements, stomach upset, nausea, and vomiting are possible.  Allergic reactions to milk thistle are rare. However, if you suffer from allergies to ragweed, daisies, marigolds, or chrysanthemums you should not use milk thistle. It is a member of the same plant family.

Interactions

Do not use milk thistle if you also smoke or drink alcohol. Milk thistle can cause toxins stored in your liver from heavy smoking, alcohol, or the use of drugs to be released in the bloodstream and enter your breast milk. Do not take milk thistle if you use the seizure medication Dilantin (phenytoin). Milk thistle can interfere with birth control pills making them less effective. It can also cause problems if you’re taking antipsychotic drugs, anti-anxiety drugs, certain cancer medications, or blood thinners. Make sure you talk to your doctor about any medications that you’re taking before you use milk thistle.   If you’re pregnant or breastfeeding, always consult your doctor before taking this or any supplement. Many herbs have side effects or interactions with other medications.

Dosage and Preparation

As noted above, due to sparse scientific data on using milk thistle to increase breast milk supply there is also limited information on ideal dosage. However, there are many products containing the herb that many breastfeeding women use.

Milk Thistle Tea

You can make a tea from the seeds of the milk thistle plant and drink it two to three times a day. Just place one teaspoon of crushed, ground, or chopped milk thistle seeds into 8 ounces (240 ml) of boiling water. Let it sit or steep for 10 to 20 minutes, and then enjoy. 

Milk Thistle Supplements

Milk thistle supplements come in capsules, soft gels, powder, and a liquid extract. It is available online and in health food or vitamin stores. If you choose to use an herbal supplement, be sure to buy it from a reputable source and follow all the directions for that particular herbal product. You should also talk to your doctor or a lactation consultant for the correct dosing information.

Milk Thistle in Food

Once you remove the spines, you can eat every part of the milk thistle plant. The seeds can be roasted or used to make tea, the leaves can be eaten raw or cooked, and the buds can be enjoyed similar to tiny artichokes.

Teas and Lactation Supplements

Milk thistle is a common ingredient found in some of the already prepared nursing teas or lactation supplements that are commercially available. It is often combined with other breastfeeding herbs such as fenugreek, fennel, goat’s rue, marshmallow root, and verbena. Always use these products as directed.

Breast Milk Supply Concerns

Milk thistle and other breastfeeding herbs may help some women increase a low milk supply. However, these treatments do not work for everyone. Other often effective actions you can take to stimulate your body to increase your breast milk supply include breastfeeding more often, breastfeeding for a longer period of time at each feeding, and using a breast pump after or between breastfeeding. The faster you can find out why you’re not making enough breast milk (or get the reassurance that you are making enough breast milk), the faster you can fix the issue and get back on track to breastfeeding successfully.

A Word From Verywell

While it’s not uncommon for breastfeeding women to experience periods of low breast milk supply, know that there are many effective measures to increase supply, such as breastfeeding more frequently and using herbs like milk thistle. Also, note that sometimes people suspect they have insufficient breast milk but actually are making enough breast milk. It can be hard to know for sure if your supply is low, so consult your doctor, lactation, and/or your baby’s pediatrician if you have any questions or concerns about your breast milk supply or if your baby is getting enough breast milk. Rest assured though that if they are gaining weight well and producing the expected wet and soiled diapers, you’re likely making sufficient quantities.