Secnidazole is structurally related to the commonly used 5-nitroimidazoles metronidazole and tinidazole. These drugs share a common spectrum of activity against anaerobic micro-organisms and they appear particularly effective in the treatment of amoebiasis, giardiasis, trichomoniasis and bacterial vaginosis. Secnidazole is rapidly and completely absorbed after oral administration and has a longer terminal elimination half-life (approximately 17 to 29 hours) than commonly used drugs in this class. in patients with intestinal amoebiasis or giardiasis, clinical or parasistological cure rates of 80 to 100% are achieved after treatment with a single dose of secnidazole 2g (30 mg/kg in children), similar to the response rates achieved with multiple dosage regimens of metronidazole or tinidazole. Patients with hepatic amoebiasis appears to respond well to 5- to 7-day therapy with secnidazole, but the efficacy of this drug regimen requires further evaluation in larger numbers of patients. After administration of a single dose of secnidazole, parasitological eradication was achieved in approximately 92 to 100% of patients with urogenital trichomoniasis. Patients with bacteria vaginosis respond at least as well to a single dose of secnidazole as to single-dose tinidazole, or single- or 7-day treatment with metronidazole; clinical improvement and/or microbiological evidence of cure was attained in approximately 59 to 96% of patients. In the clinical trials reviewed, secnidazole was well tolerated; most adverse events were gastrointestinal in nature and did not require treatment intervention or withdrawal from therapy. In summary, available evidence suggests that secnidazole is as efficacious as other 5-nitroimidazole drugs in the treatment of protozoal infections and bacterial vaginosis. The convenience and ease of administration associated with single-dose therapy, combined with a good tolerability profile, make secnidazole a suitable option to other single-dose treatments and an attractive alternative to multiple dosage regimens with other drugs in this class.