Fennel Extract: Soothing, Diuretic, Antimicrobial. The strong diuretic properties of fennel extract, as well as its ability to soothe and cool have long been known. In fact, Foeniculum Vulgare was hailed in folk medicine of the Arabian peninsula for these as well as other purposes. Women in particular often take on a puffy or bloated look in the morning, which can be effectively reduced through the use of diuretics. A less known property of this fabulous botanical is its antimicrobial activity. Fennel Extract prevents the growth of Staphylococcus aureus and Bacillus subtilis.