Updated

A soothing cup of herbal tea with star anise (search) has traditionally been heralded as an easy way to calm a colicky baby.

But before your child takes a sip, consider this. Contaminants in the herbal tea can cause dangerous neurological problems in infants.

In recent years, mounting evidence has indicated cross-contamination between Chinese star anise (llicium verum) (search), which is considered generally safe for consumption, and the closely related species Japanese star anise (Illicium anistatum) (search). The Japanese version of star anise contains potent nerve toxins (search).

Physicians reporting in the journal Pediatrics treated seven babies, aged 2 to 12 months, with signs of star anise poisoning over a two-year study period. Symptoms of toxicity in these infants included jitteriness, vomiting, irritability, jerky movements and seizures.

All infants had received at-home herbal tea with star anise at least once, although the doses may have varied in all cases from one star to six anise stars boiled in water, and given to the infants as little as once per day to as much as four times per day.

Analysis of samples of the anise star herbs used to make the herbal tea showed toxic compounds, some at very high levels.

None of the infants had abnormal labs of electroencephalograms (brain waves) and all of the infants experienced complete recovery within 48 hours of treatment.

Barbara M. Garcia Pena, MD, MPH, and co-authors say the toxicities found in the infants could be due to an overdose of Chinese star anise (which at high doses can be toxic to the nervous system), contamination with the Japanese star anise, or a combination of the two.

“Star anise tea should no longer be given to infants because of its potential danger in this population,” the authors conclude in the journal report.

On Sept. 10, 2003, the U.S. Food and Drug Administration warned consumers not to buy herbal teas brewed from star anise. The statement read: “It has come to FDA’s attention that brewed "teas" containing star anise have been associated with illnesses affecting about 40 individuals, including approximately 15 infants.”

Star anise tea is also marketed under the name Anise Estella.

By Kelli Miller Stacy, reviewed by Brunilda Nazario, MD

SOURCES: Garcia Pena, B. Pediatrics, November 2004;vol 114: pp e653-e656. News release, FDA.