There are a number of factors that may result in seeking medical advice. The first step is to obtain a referral from your GP in order to see a Gastroenterologist for whatever the related issue is.
The Australian government supports bowel cancer screening, therefore there are bowel preparation kits sent to every person once they reach the age of 50. Dr Yoganthan believes this is a valuable tool in order to prevent the risk of bowel cancer, which is one of the biggest killers in Australia. If you have not yet received a kit, you can find them at your nearest pharmacy.
If you have a family history, over the age of 50, or have any symptoms you are concerned about then a consultation visit may be in your best interest. You would need to consult your GP for a referral first.