The invention provides a method of cleansing the colon of a subject before a diagnostic therapeutic or surgical procedure comprising: administering to the subject an effective amount of a first colon cleansing solution administering to the subject an effective amount of a second colon cleansing solution the second colon cleansing solution being as defined in the application whereby the first colon cleansing solution is taken over a time period t(d1) followed by optional additional clear fluid over a time period t(cf1) and then following a time interval t(dose interval) the second colon cleansing solution is taken over a time period t(d2) followed by optional additional clear fluid over a time period t(cf2) whereby the subject undergoes the surgical therapeutic or diagnostic procedure at a time t2 after the beginning of the colon cleansing method and whereby the time interval after the completion of the second additional clear fluid and the start of the surgical therapeutic or diagnostic procedure is t(procedure interval).
