diff --git a/col.go b/col.go
index 4ed2e20..1e4d76e 100644
--- a/col.go
+++ b/col.go
@@ -260,6 +260,10 @@ func (c *FormulaCol) String(wb *WorkBook) []string {
 		c.parse(wb, true)
 	}
 
+	if wb.Debug {
+		fmt.Printf("formula col dump:%#+v\n", c)
+	}
+
 	return []string{c.value}
 }
 
@@ -404,6 +408,10 @@ func (c *LabelsstCol) Debug(wb *WorkBook) {
 }
 
 func (c *LabelsstCol) String(wb *WorkBook) []string {
+	if wb.Debug {
+		fmt.Println("metlabel sst col dump:", c.Sst, wb.sst[int(c.Sst)])
+	}
+
 	return []string{wb.sst[int(c.Sst)]}
 }
 
diff --git a/workbook.go b/workbook.go
index ec2bba6..fe48bbc 100644
--- a/workbook.go
+++ b/workbook.go
@@ -10,6 +10,7 @@ import (
 
 //xls workbook type
 type WorkBook struct {
+	Debug          bool
 	Is5ver         bool
 	Type           uint16
 	Codepage       uint16
@@ -42,6 +43,11 @@ func newWorkBookFromOle2(rs io.ReadSeeker) *WorkBook {
 	return wb
 }
 
+// SetDebug set debug flag
+func (w *WorkBook) SetDebug(debug bool) {
+	w.Debug = debug
+}
+
 func (w *WorkBook) parse(buf io.ReadSeeker) {
 	b := new(bof)
 	bp := new(bof)