In eclipse 3.8 version and earlier, you can find "Hide Toolbar" option on the right click of eclipse toolbar itself. This will hide the complete toolbar.
In Eclipse e4 versions, you can find this option in on the Eclipse toolbar Window menu.
Window -> Hide Toolbar
To enable again,
Window -> Show Toolbar
In Eclipse e4 versions, you can find this option in on the Eclipse toolbar Window menu.
Window -> Hide Toolbar
To enable again,
Window -> Show Toolbar
