The mainstay of treatment for moderate to severe ulcerative colitis and Crohn's disease is:

Corticosteroids serve as a principal treatment for moderate to severe ulcerative colitis and Crohn's disease due to their potent anti-inflammatory properties. These medications are effective in managing acute flare-ups by reducing inflammation in the gastrointestinal tract, providing rapid symptomatic relief, and improving overall patient condition.

In the context of inflammatory bowel diseases, corticosteroids are often used when patients have not adequately responded to other treatments. While they are effective for short-term management and inducing remission, long-term use poses risks, including side effects such as increased susceptibility to infection, weight gain, and osteoporosis.

While biologics are increasingly used for their ability to target specific pathways in the inflammatory process and can be beneficial for long-term management, they may not always be the first line for immediate treatment in acute situations. Aminosalicylates primarily serve as maintenance therapy rather than for acute exacerbations. Surgery can be a pivotal approach in cases where there is severe disease or complications, but it is not the mainstay treatment for active inflammation. Thus, corticosteroids remain a fundamental option for managing significant disease flares in these patients.