Disclosed is the use of a composition comprising polyethylene glycol (PEG) or PEG block copolymer in the manufacture of a medicament for use in a method for treating, ameliorating and/or preventing colorectal cancer (CRC) in humans wherein the method comprises administering approximately between 800 grams and 2365 grams of PEG or PEG block co-polymer over a period of 18 to 36 consecutive calendar months. Also disclosed is the use of a composition comprising polyethylene glycol (PEG) or PEG block copolymer in the manufacture of a medicament for use in a method of treating, ameliorating and/or preventing colorectal cancer (CRC) in humans, wherein the method comprises administering between 0.2 and 6.4 grams of PEG or PEG block co-polymer on a daily basis, wherein approximately 800 grams or greater of PEG or PEG block co-polymer is administered over a period of 24 or 36 consecutive calendar months, and wherein the composition comprises: (a) 50 – 90 % w/w polyethylene glycol (PEG), having an average molecular weight within the range 2,000 to 10,000 Da; and (b) 10 – 40 % w/w of a solid selected from the group consisting of: sorbitol, lactose, lactose and starch, dextrates, cellulose, xylitol, maltitol and mannitol; and (c) optionally further excipients optionally including flavourings, sweeteners and lubricants.