Tracking cookies are not viruses or malicious code. Cookies are only text files and therefore cannot be dangerous to your computer.
The main purpose of cookies is to identify users and possibly prepare customized web pages for them. When you enter a web site using cookies, you may be asked to fill in a form providing such information as your name and interests. This information is sent to your web browser as a cookie file. The next time you go to the same web site, your browser will send the cookie to the web server. The server can use this information to present you with custom web pages.
question "If You Want to Control Which Cookies You Accept"
If you are using a Mozilla Firefox browser, you can find more information at:
More information about cookie files can be found at:
You can also set AVG to not detect cookies on your computer. However, newer versions of AVG are set to ignore cookies (see FAQ 4433):
1. Resident Shield settings
2. AVG test settings
3. Scheduled test settings