Milk Thistle
Milk Thistle
This information describes the common uses of Milk Thistle, how it works, and its possible side effects.

Common Name

Holy thistle, Lady’s thistle, Mary thistle, Marian thistle

How It Works

Milk thistle and compounds derived from it are commonly used as herbal supplements for liver problems, but study results are mixed.

Laboratory studies suggest that milk thistle or some of its compounds have protective effects on the liver, but other animal studies suggest negative effects when combined with chronic alcohol consumption.

Studies in humans are mixed, and both a large survey and multicenter trial among patients with chronic hepatitis C did not find benefit on liver function tests with milk thistle. Other studies suggest milk thistle may reduce chemotherapy-induced hepatotoxicity in children with acute lymphoblastic leukemia and cisplatin-induced nephrotoxicity, as well as improve capecitabine-induced hand-foot syndrome and radiation therapy-induced mucositis.Topical administration of a silymarin gel was reported to reduce the severity of radiodermatitis and delay its occurrence.

Purported Uses

  • To treat alcohol-induced liver damage or cirrhosis
    Some placebo-controlled trials suggest silymarin may be helpful in treating alcoholic liver disease or cirrhosis, but more study is needed.
  • To treat hepatitis
    A large survey and multicenter trial among patients with chronic hepatitis C did not find benefit on liver function tests with milk thistle.
  • To prevent and treat drug-induced liver damage
    Laboratory, animal, and clinical trials suggest this use, although the effect varies by drug.

Do Not Take If

  • You are taking cytochrome P450 3A4 substrate drugs: Milk thistle may increase the risk of side effects of these drugs.
  • You are taking UGT (Uridine 5’-diphospho-glucuronosyltransferase) substrate drugs: Milk thistle may increase the risk of side effects of these drugs.
  • You are taking sirolimus: Milk thistle may interfere with the clearance of this drug.
  • You are taking Haloperidol or Risperidone: 7 cases of pancreatitis were reported following concomitant use of milk thistle.
  • You are taking Aripiprazole: A case of hepatotoxicity was reported with combined use of milk thistle.

Side Effects

High doses of silibinin can elevate bilirubin and liver enzymes.

Case reports
GI symptoms:
A patient experienced episodes of sweating, nausea, vomiting, diarrhea, abdominal pain, weakness, and collapse. Symptoms resolved after the patient discontinued use of milk thistle.
Severe nosebleed: In a 25-year-old man, which may have been due to self-medication with aspirin, garlic, and milk thistle. His symptoms improved following treatment.