In a three-year experiment we studied mycobiota of 24 samples of flax and 45 samples of cotton processed in Slovak textile factories. We isolated 12.2 x 10(6) (on average) cfu of microfungi per 1 g of flax samples and 3.3 x 10(5) (on average) cfu of micromycetes per 1 g of cotton samples. We also studied the ciliostatic activity of metabolites of isolated filamentous fungi on tracheal cultures of 1-day-old chicks in vitro. Twenty-nine percent of 116 investigated chloroform extracts of metabolites of microfungi isolated from flax samples stopped the cilia movement and 25% of 195 had ciliostatic activity during 72 h of experiment.