Is there any COPD treatment without gastrointestinal side effects?

Side effects... Very little of inhaled medications are absorbed systemically so bronchodilator and steroid inhalers would have few, if any, GI side effects. Systemic meds, like systemic steroids (ex. Prednisone), would have possible GI side-effects. It also depends on the GI side effects you are referring to. See your doctor for more information.