diff --git a/plugins/wordfilter/wordfilter.pl b/plugins/wordfilter/wordfilter.pl
index 6a9f57d..7f326c9 100644
--- a/plugins/wordfilter/wordfilter.pl
+++ b/plugins/wordfilter/wordfilter.pl
@@ -1,9 +1,11 @@
 
 use POSIX qw(strftime);
+use File::stat;
 
 my $filename;
-my @words;
-my $read_date;
+my $last_mtime;
+my %words_lookup;
+
 my $debug;
 my $logfile;
 
@@ -12,45 +14,57 @@ sub dolog {
     return unless $debug;
     my $ts = strftime("%Y-%m-%d %H:%M:%S", localtime);
     open(OUT, ">>$logfile");
-    print OUT "$ts $str";
+    print OUT "$ts $str\n";
     close(OUT);
 }
 
 sub refresh_words {
-    my @now = localtime();
-    my $year = $now[5];
-    my $mon = $now[4];
-    my $mday = $now[3];
-    my $dayno = 0 + ($year + 1900) * 10000 + $mon * 100 + $mday;
-    return unless ($dayno > $read_date);
-    @words = ();
+    my ($id) = @_;
+
+    my $stat = stat($filename);
+    # If the filtered words files doesn't exist, nothing to do
+    return unless $state;
+
+    # If the filtered words file hasn't been modified, nothing to do
+    $last_mtime ||= 0;
+    return unless ($stat->mtime > $last_mtime);
+
+    # The filtered words file has changed. Create a new lookup hash
+    %words_lookup = ();
     if (open(my $fh, '<', $filename)) {
         while (my $row = <$fh>) {
             chomp($row);
             next if length($row) < 1;
             push @words, lc($row);
         }
-        dolog("load from " . $filename . ", found " . @words . " words\n");
+        dolog("[$id] - '" . $filename . "' modified. Loaded " . scalar(@words) . " words.");
         close($fh);
     }
-    $read_date = $dayno;
+
+    # Create new hash for O(1) lookups
+    %words_lookup = map { $_ => 1 } @words;
+
+    # update last modified time
+    $last_mtime = $stat->mtime;
 }
 
 sub create_config {
     my ($name, $configdata) = @_;
     $filename = $configdata;
-	$read_date = 0;
-	$debug = 1;
-	$logfile = "/tmp/wordfilter.log";
+    $last_mtime = 0;
+    $debug = 1;
+    $logfile = "/tmp/wordfilter.log";
 }
 
 sub check {
     my ($id, $msg) = @_;
 
-    refresh_words;
-    foreach my $word (@words) {
-        next unless ($msg =~ /\b${word}\b/);
-        dolog("reject message " . $id . " containing `" . $word . "' in message: `" . $msg . "'\n");
+    refresh_words($id);
+    my @msg_words = split /\s+/, $msg;
+    # check each word in the message to see if has any filter words
+    foreach my $msg_word (@msg_words) {
+        next unless (exists $words_lookup{lc($msg_word)});
+        dolog("[$id] - rejecting message containing '" . $msg_word . "' in message: '" . $msg . "'");
         return 8;
     }
     return 0;