The patient who has reached steady state on warfarin should be counseled to not change the amount of dark, leafy greens eaten each day because it can affect the prothrombin time. It is more dangerous for the amount of dark, leafy greens to be decreased because the dose that helped to reach steady state is higher in the patient that eats a lot of dark, leafy greens than in the patient who eats less or no dark, leafy greens. A decrease in the dark, leafy green intake leads to less vitamin K in the system, which can cause the prothrombin time to increase, placing the patient at increased bleeding risk. The patient should also be counseled not to increase the amount of dark, leafy greens in the diet as this will decrease the effectiveness of anticoagulation. However, the potential risk of clot formation due to lower warfarin levels and atrial fibrillation is less than the actual risk for bleeding associated with elevated warfarin levels. Platelet levels can increase with exercise, but the most important instruction for the patient is to not decrease the amount of dark, leafy greens in the diet.