Food/Drug Interactions
Anticoagulants Some lettuces are rich in vitamin K, the blood-clotting vitamin produced
naturally by bacteria in the intestines. Consuming large quantities of this food may reduce
the effectiveness of anticoagulants (blood thinners) such as warfarin (Coumadin). One cup
of shredded Boston or Bibb lettuce contains 56 mcg vitamin K, about 90 percent of the RDA
for a healthy adult; one cup of shredded romaine lettuce contains 48 mcg vitamin K, about
80 percent of the RDA for a healthy adult.
Lettuce