During round one of the series of 6 instillations last year, with one week skipped between #1 & #2 due to clinic scheduling, all on Tuesdays, and a 33% strength of BCG, I had a bad headache the nights of #1 & #2, hematuria & a small clot during #6, and chills & mild burning during urination the day of each instillation. I just finished #3 in the second round on Tuesday, (#1 on a Tuesday, skip a week, #2 on a Thursday, and #3 this past Tuesday). This time on each installation day, I had much more hematuria, urination burning & mini-clots, headaches, and chills. Any of these side effects only lasted 24 hours. From other folks stories on this site, I'm lucky thus far to have far fewer side effects than most. The first cystoscopy check was in mid-December: NED. My next cystoscopy check is scheduled for March 31st. Honestly, the toughest part of BCG is the catheter insertion, which really doesn't last very long, but that I view as a small inconvenience to endure for the promise of a lower risk of recurrence or progression.