I have been taking Qualitest 10-325 for several yrs....and a couple months ago the color changed. I was told the manufacturer changed it. today I had to go to another pharmacy and they had the tablets like I had before. I want to know why these are different because of the effectiveness. I try to stay with qualitest because watson and other brands were less effective. My current script only keeps me barely above misserable. I'm not sure why there are two pills with same strength but different numbers and colors. One is yellow and 3601 and the other is white and has 3609. Both have large V on them.