This review discusses headaches secondary to disorders of homeostasis, formerly known as "headaches associated with metabolic or systemic diseases." They include the headaches attributed to 1) hypoxia and/or hypercapnia (high altitude, diving, sleep apnea); 2) dialysis; 3) arterial hypertension; 4) hypothyroidism; 5) fasting; and 6) cardiac cephalalgia. For each headache type, we discuss the clinical features and diagnosis, as well as therapeutic strategies.