The most common uses are for colds and flu, sinus infections, and other respiratory disturbances. As a supplement, elderflower also has diuretic and laxative properties and is helpful in relieving occasional constipation. Elderflower has antibacterial and antiviral properties and may also help alleviate some allergies and boost the functioning of the immune system. Elderflower might help reduce pain and swelling in joints due to some forms of arthritis and is used to stop bleeding. As an oral rinse, elderflower can be used for its antiseptic properties as a mouthwash and gargle. Elderflower also reduces blood sugar levels, very similar to the way insulin works.