I have written the code below to check and see if the text the user entered into the txtbox already exists as an item in a listbox before adding the new item. This works well; however, if say "Fish" exists in the listbox but the user entered "fish" in the textbox, the item is added to the listbox. I do not want this because the item already exists. How can I modify my code so that the comparison is not case sensitive? Any tips appreciated.

Code:
 'Check to make sure the active medication does not already exists in the list
        If lstActiveMeds.Items.Contains(strActiveMeds) = True Then
            MessageBox.Show("The active medication you entered has already been added to the list.", "Error")
            txtActiveMeds.Text = ""
            txtActiveMeds.Focus()

        Else
            'Add the Active Medication to the list
            lstActiveMeds.Items.Add(strActiveMeds)
            txtActiveMeds.Text = ""
            txtActiveMeds.Focus()

        End If