Brassinosteroids are found in a wide range of organisms from lower to higher plants. They are steroidal plant hormones implicated in the promotion of plant growth and development. Brassinosteroid metabolism has long been known to be altered in plants responding to abiotic stresses and to undergo profound changes in plants interacting with bacterial, fungal and viral pathogens. This review describes the role of brassinosteroids in response to various kinds of stresses via activation of different mechanisms. (C) 2008 Elsevier Masson SAS. All rights reserved.