Re-,
le "Généralement" me dérange un peu.....
Sinon, avec ce code de Jacques Boisgontier :
Sub test()
Dim Dico, c As Range
Set Dico = CreateObject("Scripting.Dictionary")
On Error Resume Next
For Each c In Range("A1", Range("A65536").End(xlUp))
tablo = Split(c, ",")
For Each Item In tablo
Item = Application.Trim(Item)
Dico.Add Item, ""
Next Item
c = ""
For Each k In Dico.keys
c = c & ", " & k
Next
c = Left(Right(c, Len(c) - 2), Len(c) - 2)
For Each k In Dico.keys
Dico.Remove k
Next
Next c
End Sub