A nonfatal case of poisoning involving aldicarb, an extremely toxic carbamate pesticide, is presented. A 39-year-old female ingested an unknown amount of aldicarb, together with alprazolam and sertraline. On admission to ICU (T0), she displayed marked cholinergic symptoms and a deep coma. The patient was given pralidoxime and atropine. Her condition gradually improved on days 2 and 3 and she was discharged at T0+80 h. Aldicarb was assayed by high-performance liquid chromatography on 21 blood and 8 urine samples successively taken during hospitalization. At the same time, serum pseudocholinesterase activity was followed on 21 successive samples. Blood aldicarb level was 3.11 microg/mL at T0 and peaked at T0+3.5 h (3.22 microg/mL), then followed a two-slope decay with a terminal half-life of ca. 20 h. Aldicarb was detected in all urine samples (peak level: 6.95 microg/mL at T0+31.5 h) and was still present at the time of discharge. Serum pseudo-cholinesterase activity remained low (< or = 10% of normal) until the 30th hour then rapidly increased and returned to normal after the 60th hour. The patient's clinical picture closely followed blood aldicarb levels and serum pseudo-cholinesterase activities. To our knowledge, this is the first report of an aldicarb poisoning documented by repeated measurements of the drug in the intoxicated person.