“Will a pulmonary embolism go away on its own?”

Your body will likely absorb the blood clot over time, but if your doctor is talking about starting you on treatment, that’s more to prevent further blood clots from forming that could potentially become life-threatening. 

Leslee R. McElrath, MD

A pulmonary embolism is a blood clot usually originating in the legs that breaks off from leg veins and migrates into the R heart and then into the lungs. The size of the clot can be small or large. The bigger the size, the more likely it will be clinically significant or even fatal(ie--if it is big enough to block blood flow from the right side of the heart into the lungs.)

Thus it is variable whether or not a blood clot causes major symptoms(or death) or is "stabilized" by the body and is no longer capable of causing significant or fatal consequences. But, it is a proven fact that if a patient who has a blood clot in the lower extremities is treated with blood thinners(or "clot busters"), the odds of having a pulmonary embolism(PE) and dying are MUCH REDUCED.

So, bottom line, even if a blood clot in the legs(or even if it breaks off and goes to the lungs casing a PE) may not always be fatal, it is MANDATORY that once a diagnosis of PE or DVT is made, blood thinners(or "clot busters') be started and then blood thinners be continued for a minimum of 3-6 months, and maybe indefinitely in order to reduce the chances of a fatal PE in the future.