F you notice your farts are a lot smellier than usual – and this is coupled with a loss of appetite and even weight loss – it could be a sign of Crohn’s disease.The condition can cause small-intestinal bacterial overgrowth, simply meaning too many bacteria build up in a part of the digestive system.When these bacteria break down food residue, they can produce a smelly gas.Dr Sarah says: “There are lots of symptoms to look out for if you suspect Crohn’s disease, but smelly farts accompanied by sudden appetite and weight loss could be a reason to be checked out by your GP.