An oral formulation refers to a medication designed to be taken by mouth, which can come in various forms such as tablets, capsules, liquids, and powders. These formulations are crucial for delivering drugs effectively through the gastrointestinal tract, allowing for systemic absorption into the bloodstream. In the context of certain medications, such as antihistamines and decongestants, oral formulations offer convenience and ease of use for patients dealing with allergic reactions and nasal congestion.