Adverse Effects, Cautions, Cross Drug and Herb Interactions

        I.verum is often mistaken with other Illicium species, as their structural appearances are similar to one another. More pertinent however is its confusion with Japanese star anise, I.anisatum, which is toxic (Figure 10). Recently, a rise in adulteration with I.anisatum has caused more cases of neurotoxicity within younger individuals and consequently, the U.S. Food and Drug Administration advises against its use in teas. 

Figure 10- Comparison of Japanese star anise (left) with Chinese star anise (right).
Ref: http://www.wellsphere.com/wellpage/star-anise

Therefore, caution should be taken when purchasing Chinese Star anise. Also, although I.verum is considered safe to consume and has been historically used for culinary purposes, it does contain toxic compounds veranisatin A, B and C as found in I.anisatum but only in low concentrations. Therefore, high doses or an overdose of I.verum can produce adverse neurological and gastrointestinal harm, especially in regards to young children. Symptoms of toxicity include irritability, vomiting and seizures. As previously mentioned, studies have shown that treatment of influenza with Tamiflu have caused vomiting, its only adverse effect. No cross drugs or herb interactions have been reported or found to date (Ize-Ludlow, 2004 and Philip, 2004).