Related Experiment Video
Updated: Aug 12, 2026
11:01
Moderate Prenatal Alcohol Exposure and Quantification of Social Behavior in Adult Rats
Published on: December 14, 2014
Two-year drinking-water study of formaldehyde in rats
H P Til1, R A Woutersen, V J Feron
1TNO-CIVO Toxicology, Zeist, The Netherlands.
Summary
Oral formaldehyde administration caused gastric damage in rats but did not lead to tumors. The study found no evidence of carcinogenicity from formaldehyde via this route, establishing safe exposure levels.
Area of Science:
- Toxicology
- Carcinogenicity Studies
- Gastrointestinal Pathology
Background:
- Formaldehyde is a common industrial chemical with potential health risks.
- Understanding the long-term effects of oral formaldehyde exposure is crucial for risk assessment.
Purpose of the Study:
- To evaluate the potential carcinogenicity and toxicity of formaldehyde administered orally to rats.
- To determine the no-observed-adverse-effect level (NOAEL) for oral formaldehyde exposure.
Main Methods:
- Wistar rats (70 males, 70 females) received drinking water containing formaldehyde for up to 24 months.
- Doses ranged from 0 to 109 mg/kg body weight/day.
- Comprehensive health monitoring, necropsy, and histopathological examination were performed.
Main Results:
- High-dose formaldehyde caused forestomach and glandular stomach lesions, including hyperplasia and gastritis.
- Increased relative kidney weights and renal papillary necrosis were observed in high-dose females and males, respectively.
- No evidence of tumor formation was found at any site, and no carcinogenicity was demonstrated.
Conclusions:
- Oral formaldehyde exposure at high doses causes significant gastric and renal toxicity in rats.
- The no-observed-adverse-effect levels were determined to be 15 mg/kg/day for males and 21 mg/kg/day for females.
- Formaldehyde did not exhibit carcinogenic potential following oral administration in this study.
