when using InStr function, it fills the target cell repeating info

I have the following code. I want it just to use InStr to find if a certain expression is contained within the cell, and if so perform a simple highlight action then add the date to the end of the cell's text.

used in the Sheet 'Change' event:

    If Target.Cells.Column = 1 And InStr(Target.Cells.Value,"to be opened") > 0  Then
        ActiveCell.Offset(0, 1).Interior.ColorIndex = 45
        ActiveCell.Value = ActiveCell.Value & " " & Now
        Target.Cells.Interior.ColorIndex = 0
    End If

but i just get the cell filled up with the current date/time until it can't fit anymore repeats

i've tried using target.cells.value instead of activecell, and declaring a variable with the instr value, or using a variable with the cell value inside the InStr syntax, but it always happens

i'm a bit confused

anyone know what's going on?

appreciate any help

ah, genius
works great
thanks

You're retriggering the change event when you change the cell in the event code. Not sure what logic you want, but maybe this:

Private Sub Worksheet_Change(ByVal Target As Range)
    Application.EnableEvents = False
    With Target
        If .Column = 1 And InStr(.Value, "to be opened") > 0 Then
            .Offset(, 1).Interior.ColorIndex = 45
            .Value = .Value & Format(Now, " yyyy-mmdd hh:mm")
            .Interior.ColorIndex = xlColorIndexNone
        End If
    End With
    Application.EnableEvents = True
End Sub