For several reasons, porcine colonic spirochaetosis (PCS) could be called ‘treacherous’ for pork producers. Most of the time, the disease’s symptoms are difficult to observe, nor does the disease attract attention by extreme numbers of casualties. However, when present in a herd, PCS does have a definite effect on the pigs’ performance. If medicated, research reveals, the benefitcost of controlling could be 8.8:1.