A blood clot is a clump of blood that has changed from a liquid to a gel-like or semisolid state.

Blood clotting plays an important role in the healing process of the body, but it can also create serious problems if the freezing occurs in the veins and arteries that drain blood to and from the heart. Blood clotting disorders (also called thrombophilia or hypercoagulation) are diseases that involve excessive clotting of blood, even in areas where freezing should not occur; as in blood vessels, this resulting in life-threatening conditions.Blood clotting is the body's natural way to prevent excessive blood loss.

The most common place for a blood clot to occur is in lower leg or arms, but can be happen in the heart, in the abdomen, brain, also lung. The various symptoms (depend on the size of the clot), including:

• swelling
• pain
• tenderness
• a warm sensation
• a pale or bluish discoloration.

Common factors that can put you at a moderate risk for a blood clot include:

• age, especially if you’re over the age of 65

• lengthy travel, such as any trips that caused you to sit for more than four hours at a time
• bed rest or being sedentary for long periods of time
• obesity
• pregnancy
• a family history of blood clots
• smoking
• cancer
• certain birth control pills

If you feel any of the symptoms, you need to seek medical help. In many cases, the patient consults his primary care with an internist. If symptoms are severe and affect your ability to function, you should go directly to the nearest hospital emergency department or contact an emergency health service for assistance.