The aim of this study was to continue our previously published work and to compare the different indirect diagnostic methods for hypolactasia with the lactase to sucrase ratio obtained by jejunal biopsy. The following tests were performed in 63 adult patients: the breath hydrogen test, the lactose tolerance test with ethanol (serum galactose measurement after oral lactose load with ethanol), the urinary lactose tolerance test (urinary galactose measurement after oral lactose load with ethanol), and the strip test (like the former but using a special test strip for urinary galactose). Specificities of all these tests were good (96-98%). The 3-h breath hydrogen test was less sensitive (69%) than the other methods (81-94%). The strip test is recommended for the general practitioner for the diagnosis of this common cause of abdominal complaints.