This will do it, but you may not be happy with the results since the
resulting text string may be longer than Excel allows. This code runs
from the cell pointer's current location until a blank cell is
encountered, then enters the string into cell A1. You can change the
target location by changing the cell reference in the line below that
says
range("a1").value = bdstring


sub Conc_This_Column
dim BDString as text

do until activecell.value = ""
bdstring = bdstring & activecell.value
activecell.offset(1,0).select
loop

range("a1").value = bdstring

end sub