What a bugger. I had the same happen to me. On my honeymoon!! I started Tamoxifn in February 2007 and Wedding was in October. Whilst I was on Tamoxifen (changed over to Arimidex last December when I was rediagnosed) I was in close contact with my wonderful gynecologist. Whenever I had a bleed he would investigate it as Tamoxifen has a high risk of uterine cancer associated with it. Now don't panic but get it checked out. I had many D&c and hystoscopies whilst on it. Other than that I had no other side effects on this drug. XLeonie PS I never had huge bleeds but of course I was nearly 51 when I started Tamoxifen.