(HealthDay News) -- It's important to drink plenty of water, but feeling thirsty all or most of the time can signal a medical problem.

The U.S. National Library of Medicine mentions these possible causes of excessive thirst:

• Being diabetic.
• Eating a meal that was too spicy or salty.
• Bleeding enough to cause significant blood loss.
• Taking certain medications.
• Losing too much water and salts, which could result from vomiting, diarrhea or not drinking enough water.
• Having a serious infection or burn.
• Having failure of the kidneys, liver or heart.