Irritable bowl syndrome (IBS), which affects 30 percent of the world's population, is the most widespread digestive illness. You can practice yoga to regulate the digestive tract, which is beneficial for IBS and all digestive disorders. What yoga will do is help you to treat or lessen many gastro intestinal issues in combination with dietary and lifestyle adjustments. Without such adjustments, yoga will not be able help you significantly. Yoga basically helps you to deactivating sympathetic nervous system and stimulate stimulate the parasympathetic nervous system to nourish and activate digestion and excretion.
You can practice Kapalabhati pranayama only when there are no symptoms of ibs. You can use other pranayamas like Ujjayi pranayama when suffering from diarrhoea, bloating, or gas, Shitkari and Shitali Pranayamas (but not in winter/cold season) can be used to treat constipation, acid reflux, and burning feelings.
If you think that stress has been main cause of ibs, use the relaxing techniques of Dirga and Nadi Sodhana pranayamas if stress magnifies IBS or digestive symptoms.