The term "sublingual" refers to a method of administering medication or substances under the tongue. This area has a rich supply of blood vessels, allowing for quick absorption into the bloodstream. Sublingual delivery is often used for certain medications, such as nitroglycerin for heart conditions, because it can provide faster effects compared to oral ingestion. Sublingual tablets or films dissolve quickly and bypass the digestive system, which can enhance the effectiveness of the drug. This method is also popular for some vitamins and supplements, like vitamin B12, as it can improve absorption and convenience for users.