Stimulating electrodes were chronically implanted unilaterally (in 1975-1977) in the vicinity of the locus coeruleus (LC) in three patients, one with cerebral palsy-spastic quadriplegia, two with epilepsy (one grand mal, one psychomotor). Effective excitation of efferent LC axons was indicated by measuring rises in 3-methoxy-4-hydroxyphenylethyleneglycol in the jugular and systemic venous blood following a 6-min stimulus with discontinuous bursts of pulses. There was a substantial reduction of spasticity during and after stimulation. Improvement was verified by double-blind failures of the stimulator, and the stimulus therapy is still in use after 9 years. There appeared to be a reduction in incidence and severity of both types of epileptic seizures, although this was not rigorously established. The patient with psychomotor epilepsy reported a considerable lengthening of preseizure auras (to 15-30 min), an unusual number of which terminated without a seizure.