In 65 patients with scalp psoriasis or seborrhoic dermatitis of the scalp, stool specimens, tongue swabs and scalp scales were examined for yeasts. The stool specimens showed in 70.8% of the patient group massive and in 7.7% moderate yeast colonization. Yeasts were found in 47.7% of the tongue cultures and in 12.5% of the scalp scales. Candida albicans was the predominant pathogen in the faeces and on the tongue. In comparison with a control group, frequency of yeasts in faeces and on the tongue in patients with psoriasis capillitii and seborrhoic dermatitis of the scalp could be shown to be significantly higher.