There is rapidly expanding evidence implicating alterations in the fecal microbiome in wide-ranging human diseases, including potential contributions via a gut-brain signaling axis in neurodegenerative and neuroimmunologic disorders. Proposed mechanisms such as immune modulation and the production of neurotoxins by clostridia or other microbiota could bypass an intact blood-brain barrier. To date, there are no data directly implicating the fecal microbiome in ALS, nor published case reports of FMT being tried in PALS. Data in other neurodegenerative and neuroimmunologic disorders are largely circumstantial, comprising a handful of published case reports. Therefore, ALSUntangled does not recommend FMT as a treatment for ALS at this time. However, it is plausible that the fecal microbiome plays a role in some neurologic disorders, including ALS. Given the lack of effective therapies and the relatively low cost and low risk of FMT – if performed by experienced clinical centers we support further investigations in this developing field. A reasonable next step would be a detailed molecular analysis of gut bacteria in ALS patients; certainly, these are the types of studies being advocated by the NIH Human Microbiome Project. If alterations are detected in the gut microbiome of ALS patients, a following step would be properly controlled studies in animal models, such as ALS mice. These studies could employ the same germ-free, and/or probiotic treatment regimens published in mouse models of EAE, Alzheimer’s disease, and obesity.