One hundred forty-nine (149) consecutive cases of arsenate-containing ant killer reported to the Minnesota Regional Poison Center over 4 1/2 months were retrospectively reviewed with a follow-up (1 week to 3 months) completed in 132 (89%) of the population studied. One hundred and forty eight (99%) of the ingestions were accidental. The majority of cases involved children 3 years of age and younger. Only three patients accidentally ingesting the product were symptomatic (mild episodes of vomiting and diarrhea which cleared in all patients within 12 hours). No patient was referred to a medical center for treatment and no patient reached on follow-up reported any additional ill effects as a result of the exposure. In addition to the 149 patients in this series, we describe two representative patients who accidentally ingested similar amounts of sodium arsenate-containing ant killer, resulting in urine arsenic of 3500 micrograms/24 h and 5819 micrograms/24 h. They required no chelation treatment and had no evident sequelae during 4-6 months of medical follow-up. This experience supports poison center directed home management for the majority of single, acute, and accidental ingestions of small quantities (< 5 mL) of arsenate-containing ant killers as a safe alternative to medical center referral and adverse reactions to chelation.