Water extract from silver fir (Abies alba) wood represents a rich source of lignans and other phenols that are effective in different pathological conditions, such as diabetes, cardiovascular diseases and psoriasis. Its interaction with the gastrointestinal environment is crucial when the extract is orally administered. In this study we tested the in-vitro interaction between water extract of silver fir wood and ten different Lactobacillus species that are found in the gastrointestinal tract, vagina or are used in food industry. We tested both ways of interaction: 1) the bacterial influence on the chemical composition of the extract and 2) influence of the extract on the bacterial growth. We demonstrated that the extract is compatible with all of the bacteria and does not impair their growth. Furthermore the extract acted as a prebiotic for some bacteria including: L. paracasei, L. acidophilus, L. rhamnosus, L. gasseri, L. crispatus and L. bulgaricus, suggesting that the compounds in the extract can stimulate their growth. However, the ten lactobacilli did not show any chemical changes in lignan metabolism and the production of enterodiol and enterolactone, which are considered the final metabolic products of lignans and are produced by different gut bacteria. This study indicates that the silver fir wood extract is nutritious for some Lactobacillus bacteria and can be used as a prebiotic.