The role of garlic in hepatopulmonary syndrome: a randomized controlled trial

Increased nitric oxide production in cirrhosis has been commonly implicated in the genesis of hepatopulmonary syndrome (HPS). Initial studies suggested that garlic, a constituent of the daily diet, may have a role in the treatment of HPS by altering nitric oxide production.

To evaluate the effects of oral garlic supplementation on arterial blood gas parameters, and overall morbidity and mortality in patients with HPS.

Twenty-one and 20 HPS patients were randomly assigned to receive either oral garlic supplementation or placebo, respectively, and were evaluated monthly over a period of nine to 18 months.

After nine months, garlic supplementation was associated with a 24.66% increase in baseline arterial oxygen levels (83.05 mmHg versus 66.62 mmHg; P<0.001), compared with only a 7.37% increase (68.75 mmHg versus 64.05 mmHg; P=0.02) among subjects in the placebo group. There was also a 28.35% decrease in alveolar-arterial oxygen gradient (21.35 mmHg versus 29.77 mmHg; P<0.001) among patients with HPS who received garlic, in contrast with only a 10.73% decrease (29.11 mmHg versus 32.61 mmHg; P=0.12) among those in the placebo group. After nine months, the arterial oxygen level was significantly higher (83.05 mmHg versus 68.75 mmHg; P<0.001) and the alveolar-arterial oxygen gradient was significantly lower (21.35 mmHg versus 29.11 mmHg; P<0.001) among patients receiving garlic compared with those receiving placebo. Reversal of HPS was observed in 14 of 21 patients (66.67%) on garlic supplementation (intent-to-treat analysis) and in one of 20 patients (5%) on placebo. Two of 21 patients undergoing garlic supplementation died during follow-up in contrast to seven of 20 patients who were on placebo.

Garlic supplementation may be beneficial in patients with HPS for the reversal of intrapulmonary shunts as well as reducing hypoxemia and mortality.