'Sauerkraut' was a US operation by the Office of Strategic Services to undermine the morale of the German forces in and around the Italian city of Siena (21 July 1944/April 1945).

The operation was orchestrated by Barbara Lauwers, who had been born as Bozena Hauserová during in 1914 in Brno in Austro-Hungary, and in 1931 moved with her husband from the Belgian Congo to the USA. After the USA had entered World War II, Lauwers joined the US Army and Mrs Lauwers went to work at the Czech embassy in Washington, DC, before joining the Women’s Army Corps. She was posted to Algeria and thence to Rome, where worked for the Morale Operations branch of the Office of Strategic Services.

In Rome with the rank of corporal, Mrs Lauwers assembled a team of German prisoners to work on counter-intelligence and psychological warfare matters. The prisoners worked as 'cobblers' to create false passports, visas, diplomas and other documents. Mrs Lauwers was also responsible for 'Sauerkraut', which infiltrated the German lines with teams of released prisoners to spread 'black' propaganda regarding Adolf Hitler in German-occupied Italian towns.

Mrs Lauwers also created the 'League of Lonely War Women' (or VEK in German). The task of this fictitious organisation was to demoralise German troops by making them believe that the women in their lives back home were having casual relations with other soldiers. Eight faked field post letters in German were produced by the Office of Strategic Services in Italy to a production total of 287,000 copies produced in the period between 15 July 1944 and the end of the Italian campaign in April 1945. The operation was so successful that the Washington Post was deceived and ran a story on 10 October 1944 entitled 'German soldiers on leave from the Italian front have only to pin an entwined heart on their lapel during furloughs home to find a girlfriend'. The newspaper acquired the story from a circular which had been captured on the British 8^th Army’s front and was actually written by Lauwers and carried behind German lines by 'Sauerkraut' operatives.

In another mission, Mrs Lauwers supervised a team which wrote and delivered 'black' propaganda targeting German soldiers in northern Italy. The undertaking so so successful that on 29 April 1945 some 600 troops defected.