In the most simplistic terms, platelets are the cells in your blood stream that have the function of promoting clotting. These platelets must exist in the blood stream in large numbers. If the number of platelets in the blood stream fall below a certain level, clotting time will be noticeably increased, which can cause a number of different health issues. The acceptable range for platelets in the blood stream is anywhere from one hundred and fifty thousand to four hundred and fifty thousand, with the more healthier numbers being the higher numbers. If a person is injured during a time where their platelet count is low, there is an obvious risk, but there are also unseen risks at times, where excessive bleeding can become a serious issue to an individual. Bone marrow is actually responsible for platelet production in our bodies and these platelets last about a week or more before they need to be replaced. A variety of signs can be used to infer whether or not a person has a low platelet count besides medical testing. The most obvious signs, however, will be related to whether an individual has more severe bleeding than normal. For instance, if a person cannot brush their teeth properly without triggering excessive bleeding gums, this is likely a sign of low platelet levels. Uncontrollable bleeding from minor cuts, blood in stool, blood in urine, unexplainable bruising and abnormal menstrual flow are all also signs of low platelet counts. Low platelet counts can be caused by side effects from certain medications. In fact, many people who experience low platelet counts are experiencing this problem due to the side effects from medication they are using to treat another medical problem. The body will not be able to produce platelets quickly enough to overcome platelets being destroyed from another illness and the medication being consumed for that illness. Even aspirin can cause platelet counts to drop, so be very careful in these situations. Also, low platelet counts are often a side effect of cancer and autoimmune disorders as well as the treatment for these illnesses. The spleen is responsible for removing the old platelets in our bodies, but with certain illnesses, the spleen may be removing platelets too soon, causing low platelet counts.