Three hundred sixty-seven male Wistar rats were used to compare the efficiency of urea cycle amino acids (arginine, citrulline and ornithine; Group O), furosemide (Group F), and fluid therapy (saline solution; Group FT) to treat ammonia toxicity. Rats were injected ip initially with an ammonium acetate solution at 99.9% of the lethal dose. Three min later the rats were allocated randomly to Group C (control, received 1.2 mL distilled water). Group O (amino acids listed earlier, 2 mmol/kg bw), Group F (furosemide, 2 mg/kg bw), Group FT (7mL saline), or Groups O+F, O+FT, F+FT, or O+F+FT. All treatments were given ip except for Group F given im injections. Plasma ammonia, urea and creatinine, and hematocrit and pulmonary dry matter were determined. The highest survival rates were obtained with O+FT (57%) and O+F+FT (62.5%); only 6% of the controls survived. Plasma ammonia levels were ten-fold lower in rats treated with O+FT and O+F+FT (p<0.0001). Fatally-poisoned rats had higher plasma ammonia, creatinine and hematocrit and exhibited pulmonary edema. Surviving rats had lower plasma urea. Animals given treatments with O, FT and F had (p<0.005) higher urea, lower creatinine and less severe pulmonary edema, respectively, than those untreated.