Bacterial vaginosis (BV) is a condition that is often misdiagnosed as thrush. Like thrush, it occurs when there is an imbalance of the natural bacteria and yeast of the vagina and can produce a discharge which smells of fish and is grey to yellow in nature. Similarly to Thrush, it can get worse after intercourse and may co-exist with Thrush. The exact cause of BV is unknown but is associated with a lack of the natural bacteria lactobacillus, a less acidic environment of the vagina and proliferation of organisms called mycoplasma hominis, peptostreptococcus, gardenerella vaginalis, bacteroides, and mobiluncus. Treatment is usually with a drug called metronidazole or tinidazole.