Mebendazole or Fenbendazole

People with metastatic colorectal cancer have shown slower disease progression after treatment with chemotherapy when also treated with mebendazole. Mebendazole may show similar effects in metastatic adrenal gland cancer, but no benefit and possible harm has been found among people with unresponsive (refractory) gastrointestinal cancer.

Adding mebendazole to treatment with either lomustine or temozolomide for people with recurrent glioblastoma did not have a meaningful effect.

Combining mebendazole with other therapies may show some benefits on survival and/or cancer progression:

• Mebendazole and temozolomide with high-grade gliomas
• Simvastatin, metformin, niclosamide, mebendazole, itraconazole, loratadine, and chloroquine with recurrent platinum-resistant clear-cell ovarian cancer

Preclinical evidencetesting a drug, a procedure, or another medical treatment in isolated cells or in animals; preclinical evidence is considered only an initial indication of possible effects in people (cell and animal studies) shows anticancer responses and/or longer survival in many types of cancer.

See How can mebendazole or fenbendazole help you? What the research says ›

Children treated with mebendazole for parasites showed higher percentages of probioticliving microorganisms (bacteria and some yeasts) that, when consumed in sufficient numbers, can provide health benefits that go beyond basic nutrition; benefits may include supporting gut and immune health and contributing to the maintenance of a balanced gut microbiota. Examples of probiotic foods are yogurt, kefir, sauerkraut, tempeh and kimchi and anti-inflammatory microbes. We don’t know if people with cancer would find a similar benefit.

Preclinical evidencetesting a drug, a procedure, or another medical treatment in isolated cells or in animals; preclinical evidence is considered only an initial indication of possible effects in people (cell and animal studies) shows mebendazole and fenbendazole each lower inflammation and oxidative stressan imbalance between free radicals and antioxidants in your body in which antioxidant levels are lower than normal; this imbalance can cause harmful oxidation reactions in your body chemistry.

See How can mebendazole or fenbendazole help you? What the research says ›

We could not find any published research investigating mebendazole or fenbendazole’s use for managing side effects or symptoms.

Preclinical evidencetesting a drug, a procedure, or another medical treatment in isolated cells or in animals; preclinical evidence is considered only an initial indication of possible effects in people (cell and animal studies) shows mebendazole delays the formation of some malignancies.

See How can mebendazole or fenbendazole help you? What the research says ›

• Very limited use (only one of our program sources)
• Not mentioned in oncology clinical practice guidelines

See How do experts use mebendazole or fenbendazole? ›

• One small study of people with advanced gastrointestinal cancer found that all those treated with mebendazole experienced accelerated disease progression. Extreme caution is advised and supervision by a medical professional is essential.
• Mebendazole interferes with the anticancer effects of the combined use of nitroglycerin and metformin or of disulfiram and metformin.
• Mebendazole may cause side effects such as abdominal pain, headache, diarrhea, fatigue, or anemia.
• Fenbendazole is not approved for human use in the US and the UK.
• Fenbendazole may behave as a tumor promoter when given after specific tumor initiators—substances given to animals to cause cancer in studies.
• Fenbendazole led to liver dysfunction which resolved when fenbendazole was discontinued.

See Safety and precautions ›

• Mebendazole is available with a prescription.
• Mebendazole is expensive (between $5000 US and $10,000 US).
• Fenbendazole is inexpensive (less than $500 US/year), but it is not approved for use in humans in the USA and the UK.

See Affordability and access ›