Code:
procedure TForm1.DBGrid1DrawColumnCell(Sender: TObject; const Rect: TRect;
DataCol: Integer; Column: TColumn; State: TGridDrawState);
begin
DBGrid1.Canvas.Brush.Color:=clWhite;
if Table1.FieldByName('boolean').AsString = 'true'
then
DBGrid1.Canvas.Brush.Color:=clRed;
DBGrid1.DefaultDrawColumnCell(Rect, DataCol, Column, State);
end;