Patients suffering from nausea and vomiting of pregnancy (NVP) frequently do not receive therapy, in part because of fears of adverse effects of medications on the fetus. Several vitamin-based and herbal therapies have been shown to be effective and safe. Two randomized trials of vitamin B(6) have shown a benefit in reducing NVP. Women taking periconceptional multivitamins are less likely to have severe NVP. The combination of vitamin B(6) and doxylamine (previously marketed in the United States as Bendectin) has been shown to be safe for the fetus and effective in reducing NVP. Ginger was shown, in 2 studies, to reduce NVP. Vitamin B(1) (thiamine) deficiency can lead to Wernicke's encephalopathy in women with severe NVP. Replacement is needed for all women with vomiting of more than 3 weeks' duration. Prophylaxis with multivitamins and therapy with B(6), with or without doxylamine, are safe and effective therapies for NVP.