Question:
Can someone on blood-thinning medication (aspirin, Plavix, Coumadin/Warfarin) take supplements containing vitamin K?
Answer:

We strongly suggest that anyone currently on blood thinning medications discuss the use of vitamin K-containing supplements (including the Essentials, HealthPak, and Active Calcium) with their physician.

Aspirin and Plavix, which both work by different mechanisms than Coumadin, are not generally affected by normal vitamin K intake.