You can sort the keys of a hash by value also. You can even sort them by value and by key:

my %h;
while (<DATA>) {
    chomp;
    my ($v, $k) = split;
    $h{$k} = $v;
}
print "$h{$_} $_\n" for sort { $h{$a} <=> $h{$b} || $a cmp $b } keys %
+h;
__DATA__
1 Flu
1 Cold
2 Diabetics
4 Impatience
3 Laziness
2 Hubris
3 Typhoid
4 Measle
1 Procrastination
[download]

Output:

1 Cold
1 Flu
1 Procrastination
2 Diabetics
2 Hubris
3 Laziness
3 Typhoid
4 Impatience
4 Measle
[download]