diff --git a/ChangeLog b/ChangeLog
index 38eda1c8f..2ab83f76e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2010-11-04  Robert Larice
+ * src/misc/string.c ,
+ * src/misc/stringutil.h :
+    minor modification of strtolower(), and implement strtoupper()
+
 2010-11-04  Robert Larice
  * src/frontend/plotting/x11.c :
     minor rewrite, fix a minor bug in the x11 zoom-in function
diff --git a/src/misc/string.c b/src/misc/string.c
index e6d075d78..da33d2519 100644
--- a/src/misc/string.c
+++ b/src/misc/string.c
@@ -132,10 +132,22 @@ void
 strtolower(char *str)
 {
     if (str)
-	while (*str) {
-	    *str = tolower(*str);
-	    str++;
-	}
+        while (*str) {
+            if(isupper(*str))
+                *str = (char) tolower(*str);
+            str++;
+        }
+}
+
+void
+strtoupper(char *str)
+{
+    if (str)
+        while (*str) {
+            if(islower(*str))
+                *str = (char) toupper(*str);
+            str++;
+        }
 }
 
 #ifdef CIDER
diff --git a/src/misc/stringutil.h b/src/misc/stringutil.h
index 932b43236..e53b9644b 100644
--- a/src/misc/stringutil.h
+++ b/src/misc/stringutil.h
@@ -18,6 +18,7 @@ int scannum(char *str);
 int cieq(register char *p, register char *s);
 int ciprefix(register char *p, register char *s);
 void strtolower(char *str);
+void strtoupper(char *str);
 char * stripWhiteSpacesInsideParens(char *str);
 char * gettok(char **s);
 char * gettok_instance(char **);