Natural agents that inhibit platelet aggregation include:
Garlic (Allium), either fresh, lightly cooked or in tablets of aged garlic
Chinese angelica (Angelica sinensis), found in natural food markets
Aspirin
Astragalus membranaceous (natural food markets)
Bromelain and papain (enzymes from pineapples and papaya, respectively)
Flavonoids (such as those found in re wine and tea)
Panax ginseng (Korean or Asian ginseng)
Rheum palmatum (a kind of rhubarb)
Gingko biloba (available in many formulas)
Just a reminder to anyone struggling to make sense of alternative therapies-check out The Moss Reports
http://www.cancerdecisions.com/
Ralph Moss really does a great job and his reports are very helpful in navigating the landscapes that our mainstream medical system ignores.
Good luck.