The invention provides a colon cleansing solution comprising: a) 300 to 800 mmol per litre ascorbate anion provided by a mixture of: (i) ascorbic acid and (ii) one or more salts of ascorbic acid the components (i) and (ii) being present in a molar ratio of from 1:4.5 to 1:7.0; and b) 10 to 200 g per litre polyethylene glycol. The invention also provides methods and kits associated with, or making use of the solutions, and compositions for the preparation of the solutions.