International Hangover Day is observed worldwide every first or sometimes second Saturday of August, following International Beer Day. This day was created to provide hangover recovery tips for those who may have overindulged in alcohol the previous day. The term "hangover" describes various unpleasant effects from alcohol consumption, including headache, nausea, and fatigue. While the exact causes of hangovers are not fully understood, they are believed to result from dehydration, loss of electrolytes, and sleep deprivation. Common remedies include pain relievers and rehydration, although many popular treatments lack scientific support. International Hangover Day was established after the founding of International Beer Day in 2007 by Jesse Avshalomov and the California Craft Brewers Association. It should not be confused with National Hangover Day, which is celebrated on January 1.