On 25th, July 2017, the European Medicines Agency (EMA) published a revision of the guidance on first-in-human clinical trials, that will come into effect on February 1st, 2018. The guidance addresses non-clinical issues for consideration prior to the first administration of an investigational medicinal product in humans. It also focuses on the design and conduct of clinical trials in the initial phase of single and ascending doses during the clinical development. The revised guidance aims to further help stakeholders and mitigate risks for trial participants. The first-in-human trials, in fact, represent a key step in the drug development but also a tricky moment of the process, because of the limited ability of researchers to predict the effects of a new medicine on people. The guideline puts emphasis on the sponsor’s responsibility to define the uncertainty associated with this phase, where a medicine already tested in vitro, in animals or in other preclinical studies is administered to people for the first time. The revision process has taken into account the fact that, in the past 10 years, trial protocols have become increasingly complex and aimed at assessing different aspects such as single and multiple ascending doses, food interactions, or different age groups in a single clinical protocol. The strategies to mitigate and manage risks for trial participants described in the guideline refer specifically to the calculation of the starting dose to be used in humans, the subsequent dose escalations and the criteria for maximum dose. All comments received, both on the initial concept paper and on the revised guideline, are available at this link: http://www.ema.europa.eu/ema/index.jsp?curl=pages/regulation/general/general_content_001001.jsp&mid=WC0b01ac0580029570.