Vitamin K deficiency is when there are low levels of vitamin K in the body. Vitamin K is used to produce the proteins necessary for blood clotting. There are two varieties of vitamin K. Vitamin K1 is found in green vegetables and plants, while vitamin K2 occurs naturally in the intestinal tract. 

The most common symptom of a vitamin K deficiency is excessive bleeding, but other signs include bruising easily, bleeds in the body’s mucous membranes, and dark stools.

Vitamin K deficiency is more common in infants and is relatively rare in adults. However, certain medications - such as warfarin and some antibiotics - or medical conditions, for example, celiac disease or cystic fibrosis, can hamper the body’s ability to absorb and create vitamin K.

Treatment of a vitamin K deficiency may involve dietary changes, supplements or medication. Drug classes commonly used to treat the condition are vitamin K products and some multivitamin supplements.