Five hundred eighty-six patients with epilepsy were treated with borax (hydrated sodium tetraborate) between 1912 and 1948 at the Kolonien Filadelfia Epilepsy Hospital, Dianalund, Denmark. A rough estimation shows that less than 5% experienced a more than 50% reduction in the total number of seizures. Charts were reviewed to find a connection between the concept of Bacillus epilepticus (1916) and the so-called renaissance of borax treatment described in 1923, and to find an explanation for the popularity of this seemingly ineffective antiepileptic drug.