A chronic and progressively destructive, but poorly communicable bacterial disease of the skin and mucous membranes of the external genitalia, inguinal and anal regions. One or more indurated nodules or papules lead to a slowly spreading, nontender, exuberant, granulomatous, ulcerative or cicatricial lesions. The lesions are characteristically non-friable, beefy red granulomas that extend peripherally with characteristic rolled edges and eventually form fibrous tissue. Lesions occur most commonly in warm, moist surfaces such as the folds between the thighs, the perianal area, the scrotum, or the vulvar labia and vagina. The genitalia are involved in close to 90% of cases, the inguinal region in close to 10%, the anal region in 5%–10% and distant sites in 1%–5%. If neglected, the process may result in extensive destruction of genital organs and may spread by autoinoculation to other parts of the body. Laboratory diagnosis is based on demonstration of intracytoplasmic rod-shaped organisms (Donovan bodies) in Wright- or Giemsa-stained smears of granulation tissue, or on histological examination of biopsy specimens; the presence of large infected mononuclear cells filled with deeply staining Donovan bodies is pathognomonic. Culture is difficult and unreliable. Serological tests are not useful for confirmation of diagnosis and use of the polymerase chain reaction (PCR) remains a research tool; further validation studies of these nucleic acid amplification tests are needed. Haemophilus ducreyi should be excluded by culture on appropriate selective media.