I have been on HX 500mg for last 2 weeks now plus 100mg Aspirin. I have been on Aspirin since Nov. 23 when my platelets were 840. Early this month when Hematologist started me on HX, she insisted i continue taking the Aspirin as well as they both work differently, the aspirin is watching on the clothing part of the equation but HX is reducing the excess production of platelets. My 2 cents!