Abstract Introduction: Nowadays we are looking for help and answers to our questions more and more often on the Internet. People use social networks to search for communities or groups whose members experience similar difficulties. These are often online groups that focus on psychological problems, domestic violence, etc. Members receive instant feedback and at the same time, due to the online disinhibition effect, they do not feel the fear, shame or worries they would feel in personal contact (Griffiths, 2005). The content of such self-help groups is not always helpful, but may rather induce pathological behaviour. However, the group administrator can influence the atmosphere in the group and its content itself (Niwa & Mandrusiak, 2012). Purpose: The purpose of this research was to find a space to perform professional psychological interventions inside online self-help groups on social networks. The concept of a field worker was used in this research. The field worker offers helping services to clients in an environment natural to them and where the worker can provide the client with emergency help during the crisis and prevent other clients from offering risk advices (Ambrózová, Vitálošová, & Labáth, 2006). Methods: We have conducted qualitative research using the method of content-frequency analysis. The sample for this study consisted of 10 closed online self-help groups focusing on topics such as depression, anxiety disorder, domestic violence, self-injurious and suicidal thoughts and tendencies, etc. For the purpose of this research we created an online group moderated by professionals, focusing on similar topics of mental disorders. Conclusions: The research results indicated that group members exchanged useful information (35.43%), described their current difficulties they were experiencing (32.33%), shared their own experiences (10.53%), and also published information on what had helped them manage the difficult feelings and situations they had been experiencing (6.39%). However, we also identified risky statements and threatening recommendations in posts and comments. Based on the results, we outlined the possibilities of online field worker interventions and described techniques of interventions that the professional can use for the benefit of group members.