Alkali-induced injuries of the esophagus and stomach are currently medically managed with steroids and antibiotics. We investigated whether treatment with sodium polyacrylate (PANa), a proposed mucosal protectant, could decrease the deleterious effect of alkali injuries or prevent alkali injuries. Rats were randomized in 4 groups. Group I (control; n = 7) received 0.1 ml normal saline via gastric gavage. Groups II-IV received 0.1 ml 25% NaOH. Group II (n = 22) received no further treatment. Group III (n = 9) received 0.25% PANa ad lib in drinking water for 3 days prior to NaOH. Group IV received 0.25% PANa for 6 days after NaOH. Animals were weighed daily. At 6 days post NaOH, stomachs were removed from animals in Groups II-IV and burn lesions were outlined on tracing paper. 1 x 1 cm sections of burned areas were fixed, stained with H&E and histologically evaluated. In another study, 0.1 ml of 10% NaOH was given to 2 groups of animals. Group I (n = 22) received no other treatment, while Group II (n = 13) received PANa ad lib in drinking water for 3 days prior to NaOH. Of the animals treated with 25% NaOH, only those in Group II showed a decrease mean weight which was statistically significant on Day 4, p = 0.016. Mean burn areas were statistically greater in Group II than in Group IV (p = 0.025), while histologically, lesions were similar. Pretreatment with PANa prior to 10% NaOH prevented the weight loss which occurred daily in the control animals.(ABSTRACT TRUNCATED AT 250 WORDS)