Neuro-ocular Lyme borreliosis. Any patient who has a Bell's palsy (unilateral or bilateral), aseptic meningitis, chronic fatigue syndrome, atypical radiculoneuropathy, presenile dementia, atypical myopathy, or symptoms of atypical rheumatoid arthritis should be asked specifically about the following: visits to highly endemic areas, any known tick bites, any skin lesion suggestive of erythema migrans, any history of palpitations or of prior Bell's palsy, aching in joints (especially the knees), paresthesias, chronic fatigue and depression, forgetfulness, and eye problems. Any patient showing a chronic iritis with posterior synechiae, vitritis in one or both eyes, an atypical pars planitis-like syndrome, big blind spot syndrome, and swollen or hyperemic optic discs should be asked the same questions. The physician should send one red-top tube of blood containing 2 to 3 ml serum to Microbiology Reference Laboratory, 10703 Progress Way, Cypress, CA 90630-4714, requesting a Lyme/treponemal panel. For $90 the patient will receive an RPR test with titer, serum FTA-ABS test, serum Lyme IFA IgG and IgM, and a serum Lyme ELISA test. If these tests are within normal limits and the physician is still suspicious, a Western blot can be ordered on serum. A green top tube with fresh white blood cells sent out by overnight express on a Monday or Tuesday will produce a Lyme PCR and a lymphocyte stimulation test. Finally, R.K. Porschen, director of MRL Laboratory, will provide information on the urine antigen test on an investigational basis. A careful history with emphasis on the specific questions noted above, a complete neuro-ophthalmological and physical examination ruling out other causative problems, and the laboratory studies here discussed will usually provide sufficient data to choose therapy. Much further active research into Lyme borreliosis is an important priority in medicine. 