Non-mutagenicity of urine from coffee drinkers compared with that from cigarette smokers.

The urine of human coffee drinkers who ingested 12 g of instant coffee per day, during 4 days in a first experiment or 12 g within 2 h in a second experiment, was fractionated by XAD-2 column chromatography. The non-polar urine fractions so obtained were not mutagenic in the Ames Salmonella tester strains TA98 or TA100 in either experiment, either with or without beta-glucuronidase treatment of the urine. The non-polar urine fraction of smokers, who smoked 20--30 cigarettes per day during 4 days in the first experiment or 7--18 cigarettes during 7 h in the second experiment, was mutagenic when metabolically activated.