Kefir
Kefir is a ferminted milk product which has its origins in antiquity.  It probably originated
in the Caucus Mountains of Russia and parts of the Middle East, in areas where people
often live to over 100 years of age (partially because of the kefir).  Kefir can have 30-40
probiotics (compared to yogurt which typically has 5-7 probiotics).  Kefir is made by
placing the kefir "grains" (colonies of beneficial bacteria and yeast) in milk and allowing it
to ferment for 24-48 hours.  It converts the milk sugars (lactose) into a probiotic rich
drink which can actually repopulate intestinal flora and fauna.

ANTIBIOTIC literally means "against life"; PROBIOTIC means "for life", and probiotics
are nature's internal healer.  Once you get your "gut" working properly, your body begins
to heal itself.  We have seen some truly miraculous health turnarounds when people start
drinking kefir.  If nothing else, drinking kefir at bedtime will help you go to sleep without
drugs.  I can't count how many people have told us that they slept through the night for
the first time in 5,10, 20 years after taking kefir at bedtime.  

The ultimate resource on kefir is Dom's Kefir Insite  
http://users.sa.chariot.net.au/~dna/kefirpage.html  here you will find more information on
kefir than you can probably digest (pun intended).  I won't "reinvent the wheel" by
repeating his information.