Zidoval contains metronidazole, an antibiotic gel used to treat bacterial vaginosis by reducing the bacteria responsible for the infection. Insert the gel into the vagina exactly as prescribed, usually at bedtime, and complete the full course even if symptoms improve. Avoid alcohol during treatment and for at least 48 hours after your last dose. Common side effects include vaginal irritation, a metallic taste, nausea and mild abdominal discomfort. Seek medical advice if symptoms persist or return.