The microbiota-gut-brain health axis is a complex, neurohumoral, and bidirectional communication network that occurs between various endocrine, neuronal, metabolic, and immune pathways. When this axis becomes dysregulated, several psychiatric and medical health issues may occur. Research has also found that gut-brain health axis dysfunction may contribute to problematic behaviors. During this training, participants will learn about the implications this topic has for mood, behavior, cognition, physical health,and criminality through a clinical, forensic mental health, and neurocriminological lens. A review of practical tips, strategies, and solutions that can be utilized when working with clinical and forensic mental health populations impacted by gut-brain health axis dysfunction will be discussed. Other relevant topics of interest discussed include psychogastroenterology, prenatal trauma, complex and developmental trauma, toxic stress, health disparities, eurodevelopmental disorders, nervous system dysfunction, alexithymia, sleep disturbances, substance misuse, nutritional deficiencies, and hypothalamic–pituitary–adrenal (HPA) axis dysregulation among others. Empirically based research findings will be highlighted throughout this training.