Five subjects were given 750 ml. test meals lasting 10-20 min, containing 0-300 mN citric acid, monosodium dihydrogen citrate, disodium monohydrogen citrate or trisodium citrate.1. Increase in concentration of sodium citrate in the range 0-125 mN gave increasing outputs of acid and chloride.2. The more acid the meal for any given citrate ion concentration, the less the output of acid and chloride.3. The greater the concentration of an acid citrate salt, the less the output of acid.4. There was evidence of loss of acid from the stomach by diffusion with the more acid meals.