Your urine should be a clear pale yellow colour. The colour comes from a substance known as urobilin and is the result of the normal breakdown of red blood cells.

The yellow colour gets darker when the urine becomes more concentrated. Darker shades of yellow suggest that you may be dehydrated and need water.

Your urine can be other colours, and some of these may signal a medical problem. A red colour can be caused by blood in the urine, and is a reason to see a doctor straight away. But harmless causes of redness in the urine include beetroot or blackberries in the diet.

Many of the changes to urine colour caused by medicines or diet are harmless and temporary. Orange urine can be caused by some laxatives and chemotherapy agents, and by eating carrots, because of the carotene that these vegetables contain.

Medicines that alter the colour of urine to brown include the antibiotic metronidazole, and the anti-epileptic drug phenytoin. Sennoside laxatives (Senokot) have a similar effect. Medicines such as cimetidine, which reduces stomach acid, and the painkiller indomethacin, can turn the urine green.

If you are on prescribed medicines and your urine changes colour, check with one of our pharmacists if this is an expected side effect.