Sometimes a long line of code or a long comment wraps (splits into 2 lines)
when posted on the forum. That causes an error when the cose is posted into
the VBA editor. Here is a slightly revised version which should avoid this
problem (I have also added comments to the code):

Public Sub ShowItem()
'Declare local varaiables
   Dim SelItem As String
   Dim ItemFound As Boolean, pvtItm
'Get the text entered by the user.
   SelItem = ActiveSheet.Range("A1").Value
   ItemFound = False
'Make every item in the pivottable visible.
   For Each pvtItm In ActiveSheet. _
     PivotTables("PivotTable1"). _
     PivotFields("Product").PivotItems
       pvtItm.Visible = True
'If a pivottable item matches the user's text, set
'ItemFound to TRUE (was previously FALSE).
       If pvtItm.Value = SelItem Then
           ItemFound = True
       End If
   Next pvtItm
'If no item in the pivottable matches the user's text,
'display an error message and quit.
   If ItemFound = False Then
       MsgBox SelItem & " not found in pivot table"
       Exit Sub
   End If
'Hide every item in the pivottable that does not
'match the user's text.
   For Each pvtItm In ActiveSheet. _
     PivotTables("PivotTable1"). _
     PivotFields("Product").PivotItems
       If pvtItm.Value = SelItem Then
           pvtItm.Visible = True
       Else
           pvtItm.Visible = False
       End If
   Next pvtItm
End Sub

To use this macro:
- right-click on any sheet tab in your workbook to open the VBA editor
- From the menu bar, select Insert >> Module
- Copy & paste the code above into the module
- From the menu bar, select Debug >> Compile VBAProject
- Save the workbook
- You might add a command button on your worksheet near the user input
cell. Right-click on the button and select 'View code'. In the Click event
subroutine that appears, add the code 'Call ShowItem', as follows:

Private Sub CommandButton1_Click()
   Call ShowItem
End Sub

Save, close, and re-open your workbook. The button should work.

The macro above assumes the pivvottable is named PivotTable1. To see the
name of your pivottable, click any cell in the pivottable. Then display the
Pivot Table toolbar and select Pivot Table >> Table Options. The name of your
table is displayed and can be changed in the box that appears.

Likewise, the macro assumes the pivottable field you are trying to match is
called 'Product'. Change it to the correct field name.

Hope this helps,

Hutch