Code to Change Tab Color if Data Exists

Another option:

Private Sub Workbook_SheetChange(ByVal Sh As Object, ByVal Target As Range)
If Sh.Name = "Sheet3" Then Exit Sub
If Sh.UsedRange < 1 Then Sh.Tab.ColorIndex = xlNone
If Not Intersect(Target, Sh.UsedRange) Is Nothing Then
    Sh.Tab.ColorIndex = 3
End If
End Sub

This will remove the Tab Color as well and operates on all Sheets within the workbook. If there are sheets you don't want included you need to place a line at the beginning. In the sample code above it excludes Sheet3