Brown discharge in between periods sometimes.this month it lasted for about 4 days however it got smaller in amount. no pain or pills taken. abnormal?

Possibly: If it falls roughly half way through your cycle, it could be related to ovulation. Although the discharge associated with ovulation is usually clear or white, it could turn brown from the normal bacterial growth in vagina. However, you should get an exam to rule out infection first. Also, avoid bubble bath, douching, feminine products such as vagisil.

Vaginal discharge: If it's new to you, it's abnormal. Any new, unexplained vaginal discharge should be professionally evaluated. Depending on other characteristics or symptoms (irritaion, odor, sexual risks) it could be yeast, an STD, bacterial vaginosis (an overgrowth of mostly normal bacteria), or other causes. Don't take chances -- get it checked out. Good luck!