Has anyone ever used feliway?

I have 3 cats, a 14 year old 2 and a half and1 and a half year old,recently during upheaval in my house due to rewiring and getting a new kitchen and bathroom fitted a situation occured with the cats my younger ones attacked the older of the three, we had Tasha the older checked at the vets just to make sure she was ok which she was. Since the attack Tasha is weary of the other two and a friend suggested we try a cat pheromnone called feliway and i was just wondering if any of you had ever tried it and found it helpful?