Written based on 7 research studies on PubMed, Cancer Research, Journal of Clinical Oncology, World Journal of Clinical Cases, The American Journal of Gastroenterology és Zenodo (CERN European Organization for Nuclear Research), searched on 2026. nov. 14..
The claim
Posts online say that fenbendazole helps with colorectal cancer.
Where research stands
We found it only in Cancer Research, Journal of Clinical Oncology, World Journal of Clinical Cases, The American Journal of Gastroenterology és Zenodo (CERN European Organization for Nuclear Research), and they say: A 2022 lab and animal study found that fenbendazole, a drug normally used against worms, caused colon cancer cells and tumour samples grown from patients' cells to stop dividing and die, and reduced tumours in mice. [3] A 2026 computer-modelling study asked whether fenbendazole could reach high enough levels in the body to match the doses that worked in the lab, and noted that no controlled human trials exist. [7]
We searched for fenbendazole together with colorectal cancer.
Verdict
No study we found shows that this claim is true.
Unproven means: it was only tested in animals or cells, or there is too little or mixed data from people. How we rate claims
What this means for you: Results in animals or in cells often do not hold in people. Do not stop or change your medicines because of it. Ask your doctor before you start taking it.
Sources
- Differentiating fenbendazole-induced liver injury from immunotherapy hepatitis - the importance of structured causality assessment: A case report.2026 · World J Clin Cases · Other paper
- Anti-cancer effects of fenbendazole on 5-fluorouracil-resistant colorectal cancer cells.2022 · Korean J Physiol Pharmacol · Other paper
- Abstract 2313: Fenbendazole induces cell cycle arrest in colorectal cancer cells and patient-derived colon cancer organoids2022 · Cancer Research · In animals
- A single institutional experience on patterns of ivermectin and fenbendazole use among patients with gastrointestinal cancers.2026 · Journal of Clinical Oncology · Other paper
- Letter to the Editor: Fenbendazole liver enzyme elevation in checkpoint inhibitor-treated patients as benzimidazole potentiated immunogenic tumor cell death2026 · World Journal of Clinical Cases · Other paper
- S3542 Is It Safe to Take Your Dog’s Medication? A Case of Severe Drug-Induced Liver Injury Due to Self-Administration of Fenbendazole2023 · The American Journal of Gastroenterology · Other paper
- Quantitative In Silico Reality Check on the Antiparasitic-Cancer-Cure Hypothesis: A Multi-Cancer PBPK and Network-Pharmacology Evaluation of Ivermectin and Fenbendazole Across Seven Solid and Hematologic Malignancies2026 · Zenodo (CERN European Organization for Nuclear Research) · Other paper
