To apply formatting to cells containing text only, use Conditional Formatting:
1. Select a range of cells containing text.
2. Select Home-> Conditional Formatting (in Styles Group).
3. Select New Rule -> Use a formula to determine which cells to format.
4. In Format values where this Formula is True enter the formula: =ISTEXT(A1)
5. Click Format, select the desired format from the Format Cells dialog Box, and then click OK.
6. Click OK to close the New Formatting Rule dialog box.