Here is a selection of websites that publish medical dictionaries or have information about illnesses, diseases and general health information. Please note, when you click on these websites you will be leaving the Working Carers website. The sites will open in a new browser window.
Australian websites:

This is an Australian Government initiative, funded by the Department of Health. It aims to improve the health of Australians by providing easy access to quality information about human health.
American Websites:

Med Help
Med Help International is an American not for profit website that offers patients  information about illnesses and diseases.

Medline Plus
MedlinePlus is an American website published by the US National Institutes of Health compiled from the world's largest medical library, the National Library of Medicine. The site is updated daily.

The Merc Manuals
This is an American website which publishes an online user friendly medical textbook.
The Free Dictionary

Medical Dictionary
The Free Dictionary is a project of the Farlex company. They provide a number of specialist dictionaries, including medical.