diff --git a/lib/flash.js b/lib/flash.js
index a278bc1..039ef7a 100644
--- a/lib/flash.js
+++ b/lib/flash.js
@@ -14,7 +14,7 @@ var isArray = require('util').isArray;
 module.exports = function flash(options) {
   options = options || {};
   var safe = (options.unsafe === undefined) ? true : !options.unsafe;
-  
+
   return function(req, res, next) {
     if (req.flash && safe) { return next(); }
     req.flash = _flash;
@@ -58,7 +58,7 @@ module.exports = function flash(options) {
  */
 function _flash(type, msg) {
   if (this.session === undefined) throw Error('req.flash() requires sessions');
-  var msgs = this.session.flash = this.session.flash || {};
+  var msgs = this.session.flash || {};
   if (type && msg) {
     // util.format is available in Node.js 0.6+
     if (arguments.length > 2 && format) {
@@ -68,15 +68,24 @@ function _flash(type, msg) {
       msg.forEach(function(val){
         (msgs[type] = msgs[type] || []).push(val);
       });
+      this.session.flash = msgs;
       return msgs[type].length;
     }
-    return (msgs[type] = msgs[type] || []).push(msg);
+    var ret = (msgs[type] = msgs[type] || []).push(msg);
+    this.session.flash = msgs;
+    return ret;
   } else if (type) {
     var arr = msgs[type];
-    delete msgs[type];
+    if (Array.isArray(arr)) {
+      delete msgs[type];
+    }
+    if (Object.getOwnPropertyNames(msgs).length === 0) {
+      delete this.session.flash;
+    } else {
+      this.session.flash = msgs;
+    }
     return arr || [];
   } else {
-    this.session.flash = {};
     return msgs;
   }
 }