When making drug policy, such as policy on laughing gas, many different things affect the final decision. This includes for example the cost of a solution, the vision a politician has on the subject, or research on the topic. This study demonstrates the value and role of scientific evidence in informing the policymaking process on the Royal Decree on the improper use of laughing gas of March 11, 2024. Legislative files, committee meetings and other files were evaluated to measure the use of evidence. The results show that government agency research was the most commonly cited evidence, originating from organizations like Sciensano, NICC and Centrex Traffic. A lot of the evidence was generic, meaning no source was mentioned or no evidence was available. Foundation and non-profit research from VIAS was mentioned more frequently than other research. Interestingly, policymakers led the discussions, without direct involvement of practitioners (like a doctor or garbage man) or researchers. The study found that both scientific facts and other kinds of information were used to inform the policy. While evidence is a crucial input, it should be considered alongside other relevant factors when making a policy decision. To support effective use of evidence, two key factors can be improved. First, collecting more information, including data from police and justice, can increase reliability. Second, transparency should be improved by publishing all key documents and clearly showing which evidence was used in decision-making. This helps make the policymaking process more open and allows others to better share, understand, and reuse the information. Researchers should also look into why some evidence, like the research from Vias, is used more often than others. They could do this by talking to policymakers in interviews or performing surveys to explore this. Lastly, if researchers and practitioners are more directly involved in the discussions, the decision-making process could be improved further. The study looks closely at what kind of information was used to decide which measures should be taken to regulate the use of laughing gas for improper purposes. It shows how policymakers worked with the available evidence to make their decision. This research is valuable for both policymakers and researchers, as it sheds light on how scientific evidence is currently used in policymaking and how its use can be improved. It offers researchers insights into different evidence-sharing methods, helping them better inform policymakers and contribute to a more evidence-informed policy process overall which makes the topic of great societal interest.