The Bristol Scale is a rating system which assesses the appearance of human stools (what some people call poo). It is designed to help assess the state of your bowels and can help diagnose the need for dietary changes or more serious medical conditions such as bowel cancer. The scale ranges from 1 to 7. At number 1 is poo which is hard little lumps like nuts and 7 describes a watery poo with no solid pieces. Healthy bowels should usually produce poos at 3 or 4 on the scale. These are like a sausage or snake but with cracks on the surface or like a sausage or snake which is smooth and soft. If you experience any significant change in your bowel habits that last for more than a few days you should see your doctor. Always see your doctor if your see blood or black matter in your stools and if you experience any pain in the abdomen or difficulty controlling your bowel movements.