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Redbook 2000: IV.B.2 Guidelines for Reporting the Results of Toxicity Studies November 2003

Issued by:
Guidance Issuing Office
Center for Food Safety and Applied Nutrition, Office of Food Additive Safety

Toxicological Principles for the Safety Assessment of Food Ingredients

Return to Redbook 2000 table of contents

This guidance represents the Food and Drug Administration's (FDA's) current thinking on this topic. It does not create or confer any rights for or on any person and does not operate to bind FDA or the public. You can use an alternative approach if the approach satisfies the requirements of the applicable statutes and regulations. If you want to discuss an alternative approach, contact the FDA staff responsible for implementing this guidance. If you cannot identify the appropriate FDA staff, call the appropriate number listed on the title page of this guidance.

Guidelines for reporting the results of toxicity studies are contained in this section. More complete information regarding Pathology and Statistics can be found in Chapters IV.B.3. and IV.B.4., respectively. The study report should include all information necessary to provide a complete and accurate description and evaluation of the study procedures and results in accordance with 21 CFR 58.185. The following sections should be included:

I. Study Identification and Information

  1. Study title and report number
  2. Testing facility by name and address
  3. Duration of study
  4. Dates of:
    1. Acclimation
    2. Initiation (onset of dosing)
    3. Sacrifice/termination
    4. Study report
  5. Identification and signatures (where appropriate) of personnel primarily responsible for:
    1. Conduct of the study (i.e., study director, principal investigator)
    2. Analyses of data
    3. Histopathology
    4. Writing the report
    5. Other information contained in the report

II. Good Laboratory Practice for Nonclinical Laboratory Studies Statement

The Good Laboratory Practice (GLP) regulations were designed to establish minimal standards for conduct and reporting of nonclinical safety testing and are intended to assure the quality and integrity of safety data submitted to the FDA. Each food and color additive petition, Generally Recognized as Safe (GRAS) affirmation petition, and Food Contact Notification (FCN) must include a GLP compliance statement as set forth in 21 CFR 171.1(k), 21 CFR 71.1(g), 21 CFR 170.35(c)(1)(vi), or 21 CFR 170.101(c).

III. Quality Assurance Statement

Each study report must include a quality assurance statement signed by the quality assurance unit in accordance with 21 CFR Section 58.35(b)(7) which states: "Prepare and sign a statement to be included with the final study report which shall specify the dates inspections were made and findings reported to management and to the study director."

IV. Protocol and Amendments

A protocol for each non-clinical study should be written so that it satisfies all GLP requirements set forth in 21 CFR 58.120. The protocol should include clearly stated objectives and methods for the conduct of the study. A copy of the protocol should be attached to the study report. The study report should include statements describing all changes in or revisions of the protocol, the reasons for those changes, and any influence these changes had on the results of the study.

V. Storage, Retrieval, and Retention of Records

This section of the study report should include information regarding the availability and location of original data, specimens and samples of the test substance, in accordance with 21 CFR 58.190 and 195.

VI. Summary and Conclusions

This section of the study report should contain a brief description of:

  1. Methods
  2. Summary and analysis of numerical data
  3. Summary and analysis of descriptive data (e.g., observations to assess neurotoxic potential)
  4. The conclusions drawn from the analyses, including target organ(s) and no observed effect levels (NOELs)

    The summary should highlight all significant changes in data or observations of the test substance treated groups, in comparison to the control groups, which may be an indication of toxic effects of the test substance. The summary should also include a description of the relationship between dose and the incidence/severity of lesions or abnormalities.

    The summary should include a description of all circumstances that may have influenced the quality or integrity of the data or observations.

VII. Test Substance

  1. Identification
    1. Chemical name
    2. Chemical Abstracts Service (CAS) registry number (or code number)
    3. Molecular structure and molecular weight
    4. Qualitative and quantitative determination of its chemical composition
  2. Manufacturing information
    1. Lot number
    2. Purity, including names and quantities of known contaminants and impurities and the percentage of unidentifiable materials
    3. Expiration date
    4. Stability
    5. Storage instructions
  3. Physical properties
    1. State (i.e., powder, liquid)
    2. Color
    3. Solubility, in aqueous and in dosing vehicle
    4. pH (pKa where applicable)
    5. Boiling and melting point
  4. Identification of diluents, suspending agents, emulsifiers, excipients, or other materials used in administering the test substance.
  5. Sampling of test material in administered form
    1. Times when sampling was performed
    2. Verification of stability of test compound in administered form: method and results
    3. Verification of homogeniety of test compound in administered form: method and results
    4. Verification of concentration of test compound in administered form: method and results
  6. Storage conditions: during and after the study

VIII. Test Animals

  1. Species and strain (and substrain if applicable) used and, particularly if a strain other than a common laboratory strain is used in the study, rationale for selection of the strain
  2. Source or supplier of the animals
  3. Description of any pre-test conditioning (such as quarantine procedures)
  4. Description of the method used to randomize animals into test and control groups
  5. Numbers, age, and condition of animals of each sex in all test substance treated and control groups at the beginning and end of the study
  6. Diet
    1. Feed
      1. Diet: lot number, composition, etc.
      2. Availability: i.e., ad libitum
    2. Water
      1. Availability: i.e., ad libitum
  7. Caging conditions
    1. Number of animals per cage
    2. Bedding material
    3. Ambient temperature
    4. Humidity
    5. Lighting conditions

IX. Methods

The methods section of the study report should include, but not be limited to, the following information

  1. Deviations from these Redbook 2000 guidelines
    1. Describe all ways in which the test procedure deviates from these Redbook 2000 guidelines
    2. State the rationale for each deviation.
  2. Experimental design and procedures (full description)
    1. Length of the study (including dates study began and ended)
    2. Data on dosage administration should include
      1. All dose levels administered, expressed as mg/kg body weight, per unit of time (e.g. day)
      2. Route of administration
      3. Method, frequency, and time of day of administration
      4. Total volume of dose plus vehicle administered to each animal, if the test substance is administered by gavage
      5. Duration of treatment period
    3. Observation of the test animals
      1. Duration of individual observation
      2. Frequency
      3. Method
    4. Sampling Conditions of specimens (hematology, clinical chemistry, urinalysis, other)
      1. Duration and time of day
      2. Frequency
      3. Method
    5. Statistical analyses: All statistical methods used should be fully described or identified by reference. For a complete discussion of the information that should be contained in this section of the study report, see Chapter IV.B.4.

XI. Results and Discussion

  1. Individual animal data and results should be provided in tabular format and in sufficient detail to permit independent evaluation of the results. Describe all computerized systems used in the generation, measurement, or assessment of data including the name and version of the system (software) and the specified indications for use. The following information should be included for each test animal:
    1. Time of first observation of each abnormal sign and its subsequent course. These data should be organized, when appropriate, by litter.
    2. Time of death during the study. The "most probable" cause of death should also be determined and reported for those animals that were not sacrificed at the pre-scheduled time.
    3. Feed and water consumption data (including feed spillage)
    4. Body weights and body weight changes
    5. Feed efficiency data
    6. Hematology, clinical chemistry, urinalysis, and other clinical findings
    7. Results of neurotoxicity and immunotoxicity studies, as appropriate
    8. Gross necropsy findings including:
      1. absolute and relative organ weights
      2. description of gross lesions
      3. incidence and severity of gross lesions
    9. Histopathology findings (see Chapter IV.B.3.) including:
      1. description of microscopic lesions
      2. incidence and severity of microscopic lesions
  2. Summarized data from individual animals should be organized by sex and dose group and provided in tabular format. When appropriate, data should also be organized by litter. When numerical means are presented, they should be accompanied by an appropriate measure of variability, such as the standard error. For each summarized parameter, the following information should be included:
    1. The number of animals at the beginning of the study
    2. The number of animals evaluated for each parameter
    3. The day of the study (e.g., day 60, at termination) when animals were evaluated for each parameter
  3. All numerical results should be evaluated by an appropriate statistical method. Refer to Chapter IV.B.4. for detailed guidelines about statistical considerations in toxicity studies.
  4. Evaluation of the results should include at a minimum:
    1. Discussion about the nature of relationships, if any, between exposure to the test substance and the incidence and severity of all general and specific adverse effects (such as neoplastic and non-neoplastic lesions, organ weight effects, and mortality effects), and identification of target organs.
    2. Discussion about the relationship between clinical observations made during the course of a study and post mortem findings.
    3. A conclusion statement regarding the dosage level at which no effects attributable to the test substance were observed (NOEL), and a discussion of any complex and/or any controversial issues surrounding that determination.

X. References

This section of the study report should include appropriate literature citations or references, for the following:

  1. Test procedures
  2. Statistical and other methods used to analyze the data
  3. Compilation and evaluation of results
  4. The basis upon which conclusions were reached

The above guidance document supersedes the previous version dated October, 2001.

Submit Comments

Submit comments on this guidance document electronically via docket ID: FDA-2013-S-0610 - Specific Electronic Submissions Intended For FDA's Dockets Management Staff (i.e., Citizen Petitions, Draft Proposed Guidance Documents, Variances, and other administrative record submissions)

If unable to submit comments online, please mail written comments to:

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All comments should be identified with the title of the guidance.

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