Allergan has received a subpoena from the U.S. Department of Justice, which is investigating the promotion of Botox, a drug used primarily to smooth facial wrinkles. Authorities sought documents regarding promotional, educational and other activities relating to Botox.

The subpoena comes a few weeks after regulators began reviewing the safety of Botox amid reports that there has been at least one death resulting from use of the drug. Allergan representatives said that the subpoena is probably related to alleged off-label promotion of Botox to treat headaches. Botox is not approved as a headache treatment.

Worldwide sales of Botox topped $1.1 billion in 2007.