Disodium Prednisolone 21-Phosphate is primarily used in medical treatments due to its anti-inflammatory and immunosuppressive properties. It is commonly administered to reduce inflammation in conditions such as arthritis, severe allergies, asthma, and certain skin disorders. The compound is also effective in managing autoimmune diseases like lupus and multiple sclerosis by suppressing the immune system's overactive responses.

In ophthalmology, it is utilized to treat eye inflammations, including uveitis and conjunctivitis, providing relief from swelling, redness, and discomfort. Additionally, it plays a role in managing certain types of cancers, particularly those affecting the blood and lymphatic systems, by reducing inflammation and controlling immune reactions.

The compound is often preferred in clinical settings because of its water solubility, which allows for easier administration through injections or topical applications. This makes it a versatile option for treating acute and chronic inflammatory conditions across various medical fields.