It is an open question if chemotherapy (CT) per se imposes adverse effects on salivary gland function. The aim of the present study was to investigate effects of CT on salivary function in breast cancer patients during and after adjuvant CT. Forty-five breast cancer patients, eligible for adjuvant CT with CEF or CMF (cyclophosphamide, epirubicin or methotrexate, 5-fluorouracil) were followed before, during, six months and one year after CT. Findings were compared to those in a control group of 31 breast cancer patients not receiving CT. Flow rates and compositions of unstimulated and stimulated whole saliva as well as stimulated parotid saliva (UWS, SWS and SPS) were measured. Feeling of oral dryness and saliva-related complaints were registered. UWS and SWS flow rates decreased during CT (p<0.001 and p<0.01). UWS remained lower six months after, but reached baseline level within one year. SPS flow rate was not significantly affected, suggesting that the decrease in whole saliva production is accounted for by decreased acinar saliva formation by the submandibular glands. Twenty patients (44%) suffered from hyposalivation (UWS < or = 0.1 ml/min and/or SWS < or = 0.5 ml/min) during CT. Xerostomia scores rose during CT and stayed elevated one year after treatment. CT also induced compositional changes by slightly increasing salivary sodium and chloride concentrations as well as decreasing inorganic phosphate concentrations in spite of lower or unchanged flow rates, implying that ductal modification mechanisms are affected. UWS and SWS total protein output and UWS secretory IgA output decreased in response to CT. Thus, the results suggest that acinar and ductal cell functions are affected by adjuvant CT. These adverse drug reactions are temporary, as salivary findings generally returned to baseline values within one year following treatment.