Champix/Varenicline (Chantix®, Pfizer, usually in the form of varenicline tartrate) is a prescription medication used to treat smoking addiction. By acting similarly to nicotine on the brain it reduces user cravings for cigarettes and other tobacco products and may assist some patients in smoking cessation. In May, 2006, it was approved for sale in the United States. On August 1, 2006, Pfizer announced that Chantix was available for sale in the United States, and on September 29, 2006, it was approved for sale in the European Union with the trade name Champix.

Chantix/Champix is "indicated" for (suggested for use in) smoking cessation. Chantix/Champix is an alternative to bupropion (Zyban) and nicotine replacement therapy (NRT), such as nicotine patches.

Chantix/Champix is sold as 0.5 mg and 1 mg tablets. Standard dosing of Chantix/Champix is 1 mg twice daily, with variations as permitted by the FDA. The FDA has approved Chantix/Champix use in for twelve weeks; if smoking cessation has been achieved it may be continued for another twelve weeks.

Chantix/Champix has not been tested in sub-adults (those under 18) or pregnant women yet, and therefore is not recommended for use by these groups. Women currently breastfeeding should also avoid this product, since Chantix/Champix may pass into the breast milk, leading to unknown effects to the child.