diff --git a/doc/src/sgml/ecpg.sgml b/doc/src/sgml/ecpg.sgml
index c629726affe..120d760ba21 100644
--- a/doc/src/sgml/ecpg.sgml
+++ b/doc/src/sgml/ecpg.sgml
@@ -64,8 +64,10 @@ EXEC SQL ...;
    These statements syntactically take the place of a C statement.
    Depending on the particular statement, they can appear at the
    global level or within a function.  Embedded
-   <acronym>SQL</acronym> statements follow the case-sensitivity rules
-   of normal <acronym>SQL</acronym> code, and not those of C.
+   <acronym>SQL</acronym> statements follow the case-sensitivity rules of
+   normal <acronym>SQL</acronym> code, and not those of C. Also they allow nested
+   C-style comments that are part of the SQL standard. The C part of the
+   program, however, follows the C standard of not accepting nested comments.
   </para>
 
   <para>
diff --git a/src/interfaces/ecpg/preproc/pgc.l b/src/interfaces/ecpg/preproc/pgc.l
index 6deef59d53f..f04e34a53de 100644
--- a/src/interfaces/ecpg/preproc/pgc.l
+++ b/src/interfaces/ecpg/preproc/pgc.l
@@ -394,17 +394,20 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})(.*\\{space})*.
 					xcdepth++;
 					/* Put back any characters past slash-star; see above */
 					yyless(2);
-					fputs("/*", yyout);
+					fputs("/_*", yyout);
 				}
 <xcsql>{xcstop}	{
-					ECHO;
 					if (xcdepth <= 0)
 					{
+						ECHO;
 						BEGIN(state_before);
 						token_start = NULL;
 					}
 					else
+					{
 						xcdepth--;
+						fputs("*_/", yyout);
+					}
 				}
 <xcc>{xcstop}	{
 					ECHO;
@@ -861,6 +864,7 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})(.*\\{space})*.
 							}
 						}
 					}
+<C>{xcstop}			{ mmerror(PARSE_ERROR, ET_ERROR, "nested /* ... */ comments"); }
 <C>":"				{ return(':'); }
 <C>";"				{ return(';'); }
 <C>","				{ return(','); }