Ursodiol has interesting mechanisms of action, appears reasonably safe and well-tolerated, has anecdotal reports of benefit in 6/21 of patients who report taking it, and a form of it (Yoo’s solution) was associated with slightly slower ALS progression in one out of three outcome measures within a poorly designed study that did not account for large numbers of drop-outs. However, analyses of ursodiol data from the well-conducted randomized, double-blind ceftriaxone trial show that ursodiol 300 mg twice a day is no better than placebo at prolonging survival or slowing ALS progression. Based upon this review, ALSUntangled does not recommend off-label use of ursodiol as a treatment for ALS, at least at doses of 300 mg twice a day. Determining whether higher doses or different formulations are effective will require further well-designed studies.