Abstract Background At large public events such as music festivals there is an increased exposure to the risk factors as alcohol, tobacco and narcotics, unprotected sex, trauma and violence. Non-governmental organizations engage in prevention and support activities at such events. An initiative “Be Safe Lab” has developed in Lithuania to reduce the likelihood of adverse events due to harmful behavior at public festivals. Study Aim To investigate the experience of operating the “Be Safe Lab” initiative at Lithuanian music festivals. Methods In this qualitative study the data were collected from five “Be Safe Lab” volunteer staff using semi-structured interviews lasting in average of 50 minutes. The main guidelines were prepared and informants were asked to tell in general about the initiative, motives and reasons to develop the initiative, its goals and tasks, the questions that visitors apply to them, challenges and obstacles, personal experience in the initiative. Data were analysed using inductive thematic analysis according to Braun and Clarke (2013). Results The analysis revealed 6 main themes: principles of the initiative, variety of services, substance use harm reduction, changes of volunteers' perspectives, the role of teamwork, and initiative challenges. Conclusions The initiative has a number of strengths and challenges. Integrated services are provided not just to drug users, but also to other festival visitors who seek help or advice. The volunteer staff must have special skills, competencies and medical knowledge. The harm reduction measures for drugs and psychoactive substances used in the initiative are believed to be effective and attract music festival visitors. Initiative volunteers benefit both personally and professionally from providing services. However, further success of the initiative requires additional financial support, training, and collaboration with institutions providing emergency medical services at music festivals. Key messages Integrated services are provided to any festival visitor who seek help from “Be Safe Lab” specialists. The initiative volunteers benefit both personally and professionally from providing services.