Chocolate is a trigger for some migraineurs, and not for others

Chocolate and headache are often linked, and it's true that chocolate
is a trigger for some people. But read on! Many people who think they
should avoid chocolate may not have to. Others will simply have to
avoid it no matter what. But for some, the chocolate and headache link
may be that chocolate gets rid of the headache once it starts.

The culprit may be phenylethylamine (PEA). PEA is the chemical in
chocolate that may cause the blood vessels to expand and contract.
However, it's also a natural mood enhancer, stress reliever and memory
enhancer. So once again, it may have more good than bad for some
people. The chocolate and headache connection is still unclear.

A study at the University of Pittsburgh suggested that the role of
chocolate as a migraine trigger may be over emphasized.