You need Validation on the Data toolbar.
Data Validation, in the 'Allow' box, select 'Custom' In the 'Formula' box
that appears, enter =B1=0
Use the Error Alert tab to enter a suitable error message,
Regards,
Alan.
"Carol Sitea" wrote in message
...
I need to restrict entry in one cell if there is anything in the cell next
to
it. Only one entry per line. How can I do this?

Thanks in advance,
Carol

A B
Fed Other
1 1
2 1
3 1
4 1
5 3
6 2