Approximately half of the children with ulcerative colitis (UC) have refractory, relapsing or steroid-dependent disease. UC in children is more extensive than in adults, presents more often with severe attacks and carries a more aggressive disease course. Therefore, although a step-up approach is usually recommended in UC, aggressive therapy will often be indicated in children since steroid dependency should never be tolerated. It is vital to ensure that in every resistant case, the symptoms are truly related to the inflammatory disease activity and not to other conditions such as poor adherence to treatment, infections, adverse reactions to drugs, irritable bowel syndrome, lactose intolerance, celiac disease and bacterial overgrowth. The clinician should be ready to escalate therapy in a timely manner but only after ensuring optimization of current treatments. Optimization may include, among others, appropriate dosage, utilization of assays that determine thiopurine, calcineurin inhibitors and anti-tumor necrosis factor levels, introduction of combination therapy when indicated (enemas and immunomodulators) and a long enough time for treatment to become effective. Colectomy is always a valid option and should be discussed before major treatment escalations. Experimental therapies can be considered when all else fails and the family prefers to avoid colectomy. The management of refractory and relapsing disease is particularly challenging in children, and this review summarizes the available evidence to guide treatment decisions in this setup.