Experimental induction of hepatomas, mammary tumors, and other tumors with metronidazole in noninbred Sas:MRC(WI)BR rats

J Natl Cancer Inst. 1979 Sep;63(3):863-8. doi: 10.1093/jnci/63.3.863.


Metronidazole, a chemotherapeutic agent against trichomonas infection, was tested for carcinogenicity in noninbred Sas:MRC(WI)BR rats. Three groups were given the drug for life at dose levels of 0.6%, 0.3%, and 0.06% in a powdered diet. The incidence of mammary tumors (P less than 0.020) and hepatomas (P less than 0.050) increased significantly among females given the highest dose (0.6%). Also, the rates of Leydig cell tumors of the testes (P less than 0.040) and pituitary adenomas (P less than 0.040) were statistically significant among males given the highest dose (0.6%). Results are discussed in light of a possible hazard of this drug to humans.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Carcinogens
  • Female
  • Liver Neoplasms, Experimental / chemically induced*
  • Liver Neoplasms, Experimental / pathology
  • Male
  • Mammary Neoplasms, Experimental / chemically induced*
  • Metronidazole / administration & dosage
  • Metronidazole / toxicity*
  • Neoplasms, Experimental / chemically induced
  • Pituitary Neoplasms / chemically induced
  • Rats
  • Testicular Neoplasms / chemically induced


  • Carcinogens
  • Metronidazole