Fifty-two patients, most of whom had had daily headaches for years, were examined and treated. Among them there were 40 who originally had migraine, the others had vasomotor or post-contusional headaches. Average duration of the migraine was 21 years, of chronic headache 7.6 years. All patients had been taking analgesics of a mixed type regularly and for a long time, on average 35.6 tablets or suppositories weekly. All patients had taken more than three different drugs. After an observation period of 3-6 months for grading the headaches and registering the amount of drug intake, all patients were admitted to hospital when all analgesics were at once discontinued. Changing degrees of withdrawal symptoms were the rule: increased headaches, nausea, vomiting, tachycardia, sweating, sleep disorders, and in some also hallucinations and cerebral episodes. At the end of the hospital stay chronic headache had completely disappeared or markedly improved in 77% of patients. Even after an average of 16 months of subsequent observation, chronic headache continued to be significantly improved in 70% of patients. There was a significant reduction in frequency and intensity of attacks in the patients with originally typical migraine. Regular intake of analgesics of the mixed type induces chronic headaches. These are most commonly caused by ergotamine tartrate and aminophenol derivatives, while psychological and physical dependence on anti-migraine drugs is initiated and maintained by additional barbiturates, caffeine and codeine.