Background: The International Headache Society (IHS) has published four editions of Guidelines for acute clinical trials in migraine in the past 28 years. This continuous update process has been driven by the increasing amount of scientific data in the field of migraine and by the need to continuously improve the quality of trials.

Objectives: To illustrate: i) the results of the analysis on the adherence of published trials to the 3rd edition published in 2012, in order to identify the critical areas that needed to be addressed in the 4th edition and ii) the changes introduced in this latter edition for improving adherence and methodology robustness.

Methods: We searched and reviewed all controlled trials on acute treatment of migraine published in the period 2012–2018 and we assessed their adherence to the 3rd edition of the IHS Guidelines using a score system based on the most important recommendations. Afterwards, we compared the two editions of the Guidelines and assessed the changes between them.

Results: We included data from 24 controlled clinical trials. Most trials had a randomized double-blind controlled (RDB) design, while a minority (16.7%) were non-randomized double-blind trials. Less than half (44.6%) of the RDB trials used the recommended “pain-free at 2 hours” endpoint as the primary efficacy measure. Trial design and evaluation of results were the areas that diverged the most from the recommendations.

Conclusion: Adherence to IHS guidelines for clinical trials has been suboptimal so far. The new edition has been adapted and optimized to facilitate uptake and strengthen the quality of evidence.