I m an 80 yr. old male and have been on warfarin for years with no problems. P/T 2 days ago was 2.5. First and second urination today was bloody. Never had this problem before except as result of prostate cryosurgery in 2008, which was only temporary. Subsequent PSA tests were 0.05, 0.50 and 0.73. I m on no other presciption medications and very active (tennis). I take daily supplements of vitamin C, glucosamine w/msm, B-50 complex, and selenium. If it might be a factor, I did 3 hours of yard work yesterday, primarily involving pruning of rose bushes.