Published: June 2012

Complementary Corner: Butterbur and Liver Toxicity

Prescriber Update 33(2): 16
June 2012

Healthcare professionals are advised that reports of liver toxicity associated with Butterbur have been received overseas.

The UK Medicines and Healthcare products Regulatory Agency has recently issued a safety alert warning consumers about the risks of liver toxicity associated with the use of products containing butterbur1.

Butterbur, Petasites hybridus, is a member of the ragweed family that is native to the northern United States and Canada. Butterbur is traditionally used for the treatment of hay fever, migraine and asthma.

Butterbur contains unsaturated pyrrolizidine alkaloids that are known to be hepatotoxic in humans and in preclinical studies have been shown to be carcinogenic and mutagenic2. Pyrrolizidine alkaloids may be present in low concentrations in all parts of the plant.

It is possible to reduce the unsaturated pyrrolizidine alkaloids to low levels during the manufacturing process. However, cases of liver toxicity have been reported with extracts of butterbur where the pyrrolizidine alkaloids had been removed and only small amounts remained1.

A search of the World Health Organization’s pharmacovigilance database, VigiBase, revealed reports of adverse reactions involving the liver in association with products containing Petasites hybridus3. VigiBase reports include nausea, anorexia and pruritus to hepatic enzymes increased, hepatic necrosis, hepatocellular damage, jaundice, hepatitis and hepatic failure.

In the literature, 40 cases of liver toxicity in association with butterbur have been reported1. Cases included nine of acute hepatitis and two of liver failure requiring transplantation.

Healthcare professionals are encouraged to ask patients about their use of complementary and alternative medicines and to report any suspected adverse reactions to the Centre for Adverse Reactions Monitoring (CARM).

  1. Medicines and Healthcare Products Regulatory Agency. 2012. Consumers are advised not to take unlicensed Butterbur (Petasites hybridus) herbal remedies. All Herbal Safety Warnings and Alerts 27 January 2012. URL: Generalsafetyinformationandadvice/Herbalmedicines/ Herbalsafetyupdates/Allherbalsafetyupdates/CON140849 (accessed 21 May 2012).
  2. Barnes J, Anderson LA, Phillipson JD. 2007. Herbal Medicines. London: Pharmaceutical Press.
  3. World Health Organization. VigiBase: A global individual case safety report database. Uppsala Monitoring Centre (accessed 1 May 2012).