diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml
index f7bd9650af1..2913fd79750 100644
--- a/doc/src/sgml/libpq.sgml
+++ b/doc/src/sgml/libpq.sgml
@@ -5215,7 +5215,7 @@ typedef struct pgNotify
   <para>
    <function>PQnotifies</function> does not actually read data from the
    server; it just returns messages previously absorbed by another
-   <application>libpq</application> function.  In prior releases of
+   <application>libpq</application> function.  In ancient releases of
    <application>libpq</application>, the only way to ensure timely receipt
    of <command>NOTIFY</> messages was to constantly submit commands, even
    empty ones, and then check <function>PQnotifies</function> after each
@@ -8608,6 +8608,7 @@ main(int argc, char **argv)
                     notify->relname, notify->be_pid);
             PQfreemem(notify);
             nnotifies++;
+            PQconsumeInput(conn);
         }
     }
 
diff --git a/src/bin/psql/common.c b/src/bin/psql/common.c
index a41932ff275..d257be5700f 100644
--- a/src/bin/psql/common.c
+++ b/src/bin/psql/common.c
@@ -788,7 +788,8 @@ PrintNotifications(void)
 {
 	PGnotify   *notify;
 
-	while ((notify = PQnotifies(pset.db)))
+	PQconsumeInput(pset.db);
+	while ((notify = PQnotifies(pset.db)) != NULL)
 	{
 		/* for backward compatibility, only show payload if nonempty */
 		if (notify->extra[0])
@@ -799,6 +800,7 @@ PrintNotifications(void)
 					notify->relname, notify->be_pid);
 		fflush(pset.queryFout);
 		PQfreemem(notify);
+		PQconsumeInput(pset.db);
 	}
 }
 
diff --git a/src/interfaces/ecpg/ecpglib/execute.c b/src/interfaces/ecpg/ecpglib/execute.c
index 9a6dde44de9..6f20cc412a2 100644
--- a/src/interfaces/ecpg/ecpglib/execute.c
+++ b/src/interfaces/ecpg/ecpglib/execute.c
@@ -1729,12 +1729,13 @@ ecpg_process_output(struct statement *stmt, bool clear_result)
 	}
 
 	/* check for asynchronous returns */
-	notify = PQnotifies(stmt->connection->connection);
-	if (notify)
+	PQconsumeInput(stmt->connection->connection);
+	while ((notify = PQnotifies(stmt->connection->connection)) != NULL)
 	{
 		ecpg_log("ecpg_process_output on line %d: asynchronous notification of \"%s\" from backend PID %d received\n",
 				 stmt->lineno, notify->relname, notify->be_pid);
 		PQfreemem(notify);
+		PQconsumeInput(stmt->connection->connection);
 	}
 
 	return status;
diff --git a/src/interfaces/libpq/fe-exec.c b/src/interfaces/libpq/fe-exec.c
index a97e73cf99d..916eb45d4a8 100644
--- a/src/interfaces/libpq/fe-exec.c
+++ b/src/interfaces/libpq/fe-exec.c
@@ -2239,6 +2239,9 @@ sendFailed:
  * no unhandled async notification from the backend
  *
  * the CALLER is responsible for FREE'ing the structure returned
+ *
+ * Note that this function does not read any new data from the socket;
+ * so usually, caller should call PQconsumeInput() first.
  */
 PGnotify *
 PQnotifies(PGconn *conn)
diff --git a/src/test/examples/testlibpq2.c b/src/test/examples/testlibpq2.c
index 62ecd68b55e..6cdf8c8631b 100644
--- a/src/test/examples/testlibpq2.c
+++ b/src/test/examples/testlibpq2.c
@@ -140,6 +140,7 @@ main(int argc, char **argv)
 					notify->relname, notify->be_pid);
 			PQfreemem(notify);
 			nnotifies++;
+			PQconsumeInput(conn);
 		}
 	}