The present invention relates to bicyclic labdane diterpenes for use in the treatment of a disease associated with activation of transient receptor potential cation channel 6 (TRPC6), preferably a pulmonary or a renal disease. In one aspect the invention relates to the use of a bicyclic labdane diterpene for blocking calcium transport via TRPC6. Another aspect of the invention is a bicyclic labdane diterpene according to formula (1) for use as a medicament wherein R1 is selected from hydrogen and C1 to C4 acyl, wherein the bicyclic labdane diterpene optionally comprises at least one double bond between the carbon atoms at positions 1 and 2, 2 and 3, 5 and 6, 6 and 7 and/or 14 and 15, wherein the carbon atoms at positions 1, 2, 3, 7, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 are connected to hydrogen atoms or comprise at least one substitution.
