Arsenic poisoning remains a therapeutic challenge, and outcomes are often poor. An 18-year-old man deliberately ingested termiticide containing a massive dose of arsenic trioxide. Arsenic concentration was 6.3 micromol/L in serum on ICU Day 1, and 253 micromol/L in the first 24-hour urine sample, with a urinary arsenic/creatinine ratio of 84 200 micromol/mol. He was treated with the chelating agent meso-2,3-dimercaptosuccinic acid (DMSA) (replaced by dimercaprol on Days 2-5) and required intensive support for multisystem organ failure, but recovered slowly. Nine weeks after the ingestion the only ongoing clinical issue was persistent but slowly improving peripheral neuropathy.