It looks like Roberta and Bud are both right. For salt wasters hyponatremia is possible cause of headaches. This is from: http://emedicine.com/cgi-bin/foxweb.exe/showsection@d:/em/ga?book=emerg&topicid=275 "Symptoms (of hyponatremia) may be limited to mild anorexia, headache, or muscle cramps, or the patient may present with obtundation, coma, or status epilepticus." Headache can also be a symptom of low blood sugar (hypoglycemia) This is from http://emedicine.com/cgi-bin/foxweb.exe/showsection@d:/em/ga?book=ped&topicid=1117 "The body normally defends itself against hypoglycemia by decreasing insulin secretion and increasing glucagon, epinephrine, growth hormone and cortisol secretion." "Non specific symptoms (of hypoglycemia) include mouth tingling, dry mouth, blurred vision, headache and nausea" Before taking extra medication, I would first try eating something salty and taking a long drink of water. If the cause of the headache is low blood sugar then eating a piece of fruit would likely be helpful. Joan