A 32-year-old woman, living in Paris, was admitted to our hospital because of ascending weakness and paresthesiae in the lower limbs, associated with dysuria. One month before admission, she had thoracic pain in the left T10 dermatome, abdominal pain and diarrhea, that resolved spontaneously within a few days. Examination confirmed distal asymmetric weakness and dysesthesiae in both lower limbs, up to right T12 and left L1 dermatomes. Deep tendon reflexes were present and symmetric. Right cutaneous plantar response was in extension. There was no meningeal irritation and no rash. Spinal magnetic resonance imaging (MRI) showed intramedullar T2-weighted hyperintensity from T6 to T11, with a contrast-enhancement at level T9 (Fig. 1). CSF examination revealed 25 cells/μL with 50 % of eosinophils, 28 % of lymphocytes, 0.3 g/L of protein and 3.3 mmol/L of glucose. Hematological, biochemical, inflammatory, and immunological blood tests were normal or negative, and the number of peripheral blood eosinophils was within the normal range. HIV serology was negative. Viral polymerase chain reactions in the CSF were negative for HSV, VZV, CMV and EBV. Antibody titers against schistosomiasis, cysticercosis, hydatidosis, amoebiasis and toxoplasmosis were negative in serum. There was no cryptococcus in either the blood or CSF. No parasitic organism was detectable in either the feces or urine. However, antibody titer against Toxocara canis was positive using the ELISA method and was higher in the CSF than in serum (200 in the CSF vs 62 in the serum), suggesting intrathecal Toxocara canis antibody synthesis. Consequently, acute meningo-myelitis due to Toxocara canis was diagnosed. Although symptoms partially disappeared before any treatment, IV administration of mebendazole (800 mg per day for 10 days) was concomitant with an almost complete clinical recovery and total normalization of spinal MRI (Fig. 2).