Intestinal Microbiome Transplant in ALS

Inclusion Criteria:

* Diagnosis of ALS according to Gold Coast Criteria
* Age: 18+ years at enrollment
* Fast-progressing (ALSFRS-R change of at least 1.5 points per month between last 2 measurements at screening)
* Modestly but not severely affected (ALSFRS-R score at or above 24 at screening)
* Able to swallow capsules and expected to be able to for the duration of the trial (ALSFRS-R "swallowing" score of 3 or 4 at screening)
* Expected to survive for the duration of the trial
* Taking any combination of riluzole, edaravone, and/or tofersen at a stable dose for 30 days prior to screening, or not taking any of these and not expected to during the study.
* Capable of giving written consent.
* If sexually active, must agree to use contraceptive or abstinence for duration of treatment.
* Females of child-bearing age must have negative pregnancy test at screening.

Exclusion Criteria:

* Concurrent illness or laboratory abnormalities that could confound the measurement of ALS progression or the microbiome or interfere with the ability to complete the study.
* Taking probiotics, nutraceuticals, or herbal remedies within 2 weeks of screening
* Taking antibiotics within 3 months of screening.
* Taking any investigational study drug within 30 days of screening or five half-lives of the prior agent.
* Previous exposure to MTT.
* Pregnancy.
* Known specific food allergy with anaphylaxis
* Other co-morbid conditions that, in the opinion of the study investigator, place the participant at increased risk of complications, interfere with study participation or compliance, or confound study objectives.