What is fennel oil? Fennel oil is obtained by steam distillation of the dried fruits of Foeniculum vulgare. The oil is pale yellow to brownish-yellow in colour. The product has a characteristic sweet, green, earthy, spicy note. Anethole and fenchone are major components in Fennel oil Fennel oil is a remedy for digestive complaints such as flatulence, constipation, colic, nausea, vomiting, anorexia, dyspepsia and hiccups. It is also used in cases of obesity, as it promotes that 'full feeling' and has a diuretic effect that helps to disperse cellulite