**Background**
Neurological disorders are a major cause of disability and death worldwide. Recent research has revealed that the gut microbiome, comprising trillions of microorganisms, plays a crucial role in brain health via the microbiota-gut-brain axis—a bidirectional communication network involving neural, endocrine, immune, and metabolic pathways. This mini-review focuses on three common neurological disorders—epilepsy, Parkinson’s disease (PD), and migraine—chosen for their high burden on healthcare systems. The authors aim to provide a brief overview of the relationship between the gut microbiota and these conditions, and to discuss potential microbiome-based diagnostic and therapeutic strategies.
**Methods**
This is a narrative mini-review. The authors synthesized existing literature on the microbiota-gut-brain axis and its association with epilepsy, PD, and migraine. No systematic search strategy or inclusion/exclusion criteria are reported. The review draws on studies cited in the reference list, including animal and human research, but does not specify databases, search terms, or quality assessment methods.
**Key Results**
- **Epilepsy**: Over 70 million people worldwide have epilepsy, with 60% of cases idiopathic. More than 30% of patients have refractory epilepsy (uncontrolled by medication). The ketogenic diet (high fat, low carbohydrate) is a common therapy, and its efficacy may be mediated by changes in gut microbiota composition. Small sample size studies show differences in fecal microbiota between epileptic patients and healthy controls, and between patients before and after ketogenic diet therapy. Dysbiosis is observed in epileptic patients, and the gut microbiota influences the glutamine-glutamate-GABA cycle and GABA receptor expression.
- **Parkinson’s disease**: PD affects 7–10 million people globally. Over 80% of PD patients experience gastrointestinal symptoms, which often precede motor symptoms. Alpha-synuclein pathology is found in both the central and enteric nervous systems, suggesting that PD may originate in the gut. Gut microbiota composition differs between PD patients and healthy individuals. Germ-free animals show protection against neuronal loss. Microbial treatments such as probiotics and fecal microbiota transplantation may help with motor and nonmotor symptoms.
- **Migraine**: Migraine affects about 18% of females, 6% of males, and 2% of the global population have chronic migraine. It is the second most common cause of disability worldwide. Migraine is associated with gastrointestinal disorders (celiac disease, irritable bowel syndrome, Helicobacter pylori infection). Gut microbiota differs between migraine patients and healthy controls. Microbial alterations may increase calcitonin gene-related peptide release and modulate tumor necrosis factor alpha signaling in the trigeminal nerve system. Vagus nerve stimulation can reduce migraine pain. The ketogenic diet and probiotics may help control migraine episodes.
**Clinical Implications**
The review suggests that the gut microbiome is a promising target for both diagnosis and treatment of epilepsy, PD, and migraine. For epilepsy, the ketogenic diet’s effects may be mediated by gut microbiota remodeling, offering a potential therapy for refractory cases. In PD, monitoring gut microbiota changes could enable earlier diagnosis, and probiotics or fecal microbiota transplantation might alleviate symptoms. For migraine, dietary interventions (e.g., ketogenic diet) and probiotics may reduce attack frequency and severity. However, the authors emphasize that more research is needed to establish causality and develop standardized microbiome-based interventions. The review is limited by its narrative design, lack of systematic methodology, and reliance on small or preliminary studies.