Fasting is a known trigger for headache. More specifically, headache associated with ritual fasting in compliance with religious edict has been documented and described in the literature. These have been described in Jewish and Muslim ritual fasts, and have been dubbed 'Yom Kippur headache,' and 'First of Ramadan headache' respectively. The incidence of fasting associated headache during the 25 hour fast of Yom Kippur (YK) wherein no food or drink is ingested, has been documented in approximately 40% of participants, but as high as 66% of those prone to headache. (1) A recent study was published in which the authors were able to show a marked reduction in YK headache using rofecoxib 50mg, a Cox 2 specific nonsteroidal anti-inflammatory medication with a relatively long (17 hour) half life. In a placebo controlled double blind randomized trial, in a population with a history of fasting headache, the drug was ingested just prior to the start of the fast. The placebo group had an incidence of headache 65% of the time whereas the treatment group had an incidence of 19%. Headache in the treatment set was also on average milder than in the controls. These results were all significant statistically. (3)