In the case of co-infection, the pus is yellow in color, viscous in texture, and most of the time smells fishy. Of course, if there is a rupture of capillaries, the pus will have a bloody discharge. There is also a case of tuberculous anal fistula, where the pus is generally thin, watery or yellowish, and does not have a very specific odor. Most of the time, the pus will be taken for bacterial culture and drug sensitivity to see which bacterial infection is caused, and then targeted antibiotics for anti-inflammatory treatment. This anti-inflammatory treatment is usually done after surgery and requires about a week of anti-inflammatory treatment.