BACKGROUND: `Fake nail' cosmetics are a growing, $265 million business in the U.S. Whereas previously artificial nails were applied by cosmeticians in salons, home application of fake nails has recently become more popular. Many artificial nail products available to consumers for home use may contain methacrylic acid (MAcid), a known corrosive. These products are not contained in child resistant packaging. OBJECTIVE: To estimate the hazard to children from MAcid-containing nail products. DESIGN/METHODS: Analysis of 1993-95 Toxic Exposure Surveillance System (TESS) data compiled by the American Association of Poison Control Centers (AAPCC). Injuries from MAcid-containing nail products were analyzed by age, injury type, and outcome. A comparative hazard score (HS) was calculated based on morbidity as a fraction of total product exposures, normalized to that of all other products in the dataset. RESULTS: Of 71,033 nail product exposures in 1993-95 TESS, 759 calls (1.1%) concerned exposures to MAcid nail products, of which 655 (86%) occurred in the home. In 566 (74.6%) exposures to MAcid-containing products, children less than 6 yrs were involved. Of these, 56 children (9.9%) suffered `moderate' and 3 (0.5%) suffered `major' injuries. Fifty of the 59 preschoolers (84%) had predominately dermal, oral, and/or eye burns. The calculated HS for these products was 8.6. Compared to published HS of other household products, MAcid nail products were as hazardous as anti-freeze (HS=9.6), kerosene (HS=7.9), and ethanol-containing beverages (HS=8.0), and were much more hazardous than other cosmetics (HS=0.2), mothballs (HS=0.5), or even oven cleaner (HS=3.5). CONCLUSIONS: Methacrylic acid-containing artificial nail products are hazardous to young children and require better injury prevention measures. They should be sold in child resistant containers, accompanied by appropriate warnings to consumers.