The disclosure provides compositions for use in purgatives, for use as purgatives, and to methods for inducing purgation of the colon. The composition comprising between 1 and 20 grams of at least one water-soluble sodium salt； between 0.1 and 4.8 grams of at least one water-soluble potassium salt； between 0.1 and 7 grams of at least one water-soluble magnesium salt； erythritol； and a bisoxatin (or 2,2-bis(4-hydroxyphenyl)-2H-benzo[b][1,4]oxazin-3(4H)-one), or bisoxatin acetate, or equivalent. In alternative embodiments, the disclosure provides compositions, e.g., a purgative, comprising: a water-soluble sodium salt (especially sodium sulphate), a water-soluble potassium salt (especially potassium sulphate), and a water-soluble magnesium salt (especially magnesium sulphate)； and, compositions further comprising: a bisoxatin, or a detergent stool softening agent (such as sodium picosulphate) and/or a water-soluble sugar (such as xylose or equivalent)； or, compositions having these ingredients at different amounts, but at equivalent proportions. In alternative embodiments, the disclosure provides purgative compositions comprising electrolytes, salts, sugars, bisoxatin, dyes and biofilm disruptors. An example of a composition comprises bisoxatin, sodium, potassium and magnesium electrolytes and erythritol.
