Covering: 2002 to 2004. Previous review: Nat. Prod. Rep., 2002, 19, 617–649

The literature on guanidine-bearing natural products is reviewed, with emphasis on occurrence, isolation, structure determination, biosynthesis, synthesis and biological activities, with 365 references. The literature survey includes macrocycles and peptides from bacteria and cyanobacteria, as well as alkaloids and peptides isolated from marine and terrestrial invertebrates and higher plants.