To improve data availability in health risk assessment of chemicals and fill information gaps there is a need to facilitate the use of non-standard toxicity studies, i.e. studies not conducted according to any standardized toxicity test guidelines. The purpose of this work was to propose criteria and guidance for the evaluation of reliability and relevance of non-standard in vivo studies, which could be used to facilitate systematic and transparent evaluation of such studies for health risk assessment. Another aim was to propose user friendly guidance for reporting of non-standard studies intended to promote an improvement in reporting of studies that could be of use in risk assessment. Requirements and recommendations for the design and execution of in vivo toxicity studies were identified from The Organisation for Economic Co-operation and Development (OECD) test guidelines, and served as basis for the data evaluation criteria and reporting guidelines. Feedback was also collected from experts within the field of toxicity testing and risk assessment and used to construct a two-tiered framework for study evaluation, as well as refine the reporting guidelines. The proposed framework emphasizes the importance of study relevance and an important aspect is to not completely dismiss studies from health risk assessment based on very strict criteria for reliability. The suggested reporting guidelines provide researchers with a tool to fulfill reporting requirements as stated by regulatory agencies. Together, these resources provide an approach to include all relevant data that may fill information gaps and reduce scientific uncertainty in health risk assessment conclusions, and subsequently also in chemical policy decisions. Copyright © 2014 John Wiley & Sons, Ltd.