PARACETAMOL KINETICS AND GASTRIC EMPTYING Sir,—We are investigating immediate post-partum gastric function and the influence of metoclopramide on it, using paracetamol absorption kinetics as a measure of gastric emptying (Heading

We believe that aspiration of food particles is hazardous even when the pH is >2.5. Wynne and associates (1979) demonstrated that the aspiration of paniculate gastric contents at a pH of 4.3 was associated with severe lung injury. Moran (1951) found the pathological changes caused by non-acidic ground food aspiration in the guineapig to be identical to food aspiration pneumonia in man. Schwartz and co-workers (1980) add further support to this contention by demonstrating that aspiration of gastric contents with a pH of 5.9 was associated with changes consistent with pneumonitis. These findings on paniculate matter may contradict the classic findings on Mendclson's syndrome (Mendelson, 1946). Miller's study does not examine the effect of a light breakfast on the amount of paniculate matter in the stomach. The discomfort involved in fasting seems insignificant compared with the risks incurred by aspiration of foods. Aspiration of paniculate matter clearly can be associated with severe morbidity and should be avoided. We therefore encourage the continued practice of fasting patients for at least 4 h before elective surgery.