Flu & Cold:

"Garlic kills viruses responsible for colds and the flu, according to tests
by James North, a microbiologist at Brigham Young University. " -
http://www.usaweekend.com/health/carper_archive/950402eat_smart_garlic.html

Also, I believe, zinc has been shown to reduce the symptoms by 2/3rd's.  So
eating foods high in zinc is a great paleo way to fight the cold/flu
(meats, chicken, seafood, nuts).

Kat.