In a rabbit model, a variety of hyperalimentation solutions have been shown to have an adverse effect on the right atrium, pulmonary artery and pulmonary parenchyma when infused for one week into the right atrium. High concentrations of dextrose combined with amino acids produced the greatest morbidity and mortality. No clear relation exists between pH or osmolarity and toxicity. The pulmonary injury seen in this model may explain the occasional development of pulmonary hypertension in patients receiving long term total parenteral nutrition.