The paper surveys available grammatical descriptions of Czech causal expressions and their explanation in textbooks of Czech for foreigners and provides a detailed description of variant causal expressions, focusing on their meaning, frequency, and syntagmatic properties, taking advantage of onomasiologically (semantically) oriented corpus research. The analysis of L2 Czech textbooks for above the threshold levels (B2 and C1) has revealed that the explanation of causal expressions is far from satisfactory and does not allow non-native speakers to use formal variants adequately. It is suggested that comprehensive linguistic description of causal expressions based on their semantics and corpus studies could be helpful in overcoming the defici...