While accessing a data from a list where we have rich text editor, We might get an unexpected problem.
While getting the data from list item columnusing listitem["Column Name"], in case of rich text field, we get entire HTML data.

This might be a problem when you are doing a custome web part and retrive data .
The HTML might break some of ur desired HTML.Lets say if you need your entire string to be stripped off all tags, Below code will be helpful.

plainText= Regex.Replace(html, @"]*>", "");

Use namespace System.Text.RegularExpressions to make Regex available. html is variable having the HTML content