Fennel is used in cooking and is generally safe. Fennel seed and oil are the part of the plant used for medicinal purposes. As a supplement, fennel is commonly used for upset stomachs, but research isn’t strongly conclusive. Research supports the use of fennel for colicky babies, although two cases of infant neurotoxicity were reported from breastfeeding women who drank herbal tea with fennel.
Attention for Liver Disease: May alter liver laboratory results.
Safety Information: Fennel is generally safe. Allergic reactions are common. Seizures have been associated with fennel oil use. Avoid if history of seizures. Diabetics should use cautiously fennel that is prepared in syrup or honey. Probably safe for children if taken in small doses. Safety for pregnant or breastfeeding women is unknown.
Interactions: Do not take within 2 hours of taking ciprofloxacin. May interact with hormones and birth control pills.
Lab Notes: May alter liver function tests and blood-clotting times. May lower blood pressure, cholesterol and blood glucose levels.