A pint of the black stuff a day may work as well as a low dose aspirin to prevent heart clots that raise the risk of heart attacks.
Drinking lager does not yield the same benefits, experts from University of Wisconsin told a conference in the US.
Guinness were told to stop using the slogan decades ago – and the firm still makes no health claims for the drink.
The Wisconsin team tested the health-giving properties of stout against lager by giving it to dogs who had narrowed arteries similar to those in heart disease.
They found that those given the Guinness had reduced clotting activity in their blood, but not those given lager.
I â™¥ Guinness and Stout Beer in general.