Yes there is some green slimey stuff in a can that fills up and seal the tube to get you home, but.... and that is a big but, you've got to remove the nail or whatever punctured the tyre and.... if there is any leak of this green goo in the actual tyre casing, when you do replace the tube you will have a hard time scraping it all off the inside of the tyre, like trying to remove superglue from your skin.