Radiotherapy of the head and neck region, which includes the major and minor salivary glands in the radiation field, usually leads to temporary or permanent xerostomia. This may affect eating and increase the risk of inadequate intake of energy and nutrients. The aim of the present study was to investigate the effects of radiotherapy-induced xerostomia on energy and nutrient intake in individuals treated for malignancies in the head and neck region. The dietary intake of 24 patients with a low chewing stimulated whole saliva flow rate (< 0.5 ml/min) and in age and sex matched controls with normal flow rate (> 1.0 ml/min) was recorded for 7 days. The average daily energy intake was nearly 300 kcal lower in the irradiated patients with dry mouth symptoms than in the control group. The mean intake in the former group was 1925 kcal per day whereas the control group had an intake of 2219 kcal per day. Irradiated patients with dry mouth symptoms had significantly lower mean intakes of vitamin A, beta-carotene, vitamin E, vitamin B6, folacine, iron and zinc than those in the control group. There was also a lower intake of vitamin C, but this was not statistically significant. The intake of vitamins A and C exceeded or reached the levels recommended in the Swedish Nutritional recommendations, but the average intakes of fibre, iron, beta-carotene, vitamin E, zinc, selenium, and iron did not reach recommended levels, in neither the experimental nor the control group. There was a slight positive correlation between energy intake and saliva secretion rate in the control group, but the energy intake was totally independent of variations in secretion rate in the irradiated patients with low secretion rate.