Two of the symptoms that are associated with pregnancy are nausea and vomiting. This condition can cause temporary disability and it has been observed with employed women that have as much as 25% of nauseous pregnant women require to time off from work.

The exact cause of nausea and vomiting during pregnancy is still unknown. A wide variety of treatments are used, but due to the potential harmful effects to the fetus, the use of drugs is limited.

Ginger has been suggested as an alternative treatment to control nausea and vomiting, but data on its efficacy are limited. In one study, ginger was found to be superior to dimenhydrinate, a medicine commonly used in reducing motion sickness. In another study, ginger was found to significantly reduce postoperative sickness. To determine the effectiveness of ginger for the treatment of nausea and vomiting of pregnancy, this study was conducted.

Included in the study were pregnant women with nausea and vomiting who first attended a clinic at or before 17 weeks of gestation. During a five-month period, 70 eligible Thai women gave consent and were randomized to receive orally one-gram per day of either ginger or an identical placebo over a four-day period.

Subjects used a visual analog scale to grade the severity of their nausea and recorded the number of vomiting episodes in the previous 24 hours before treatment, and again during the four consecutive days while taking treatment. At a follow-up visit seven days later, five-item Likert scales were used to measure the severity of their symptoms.

The median change in nausea scores was significantly greater in the ginger group compared to the placebo group. After four days of treatment, the ginger group had significantly fewer vomiting episodes than the placebo group. The overall subjective report of their symptoms revealed that the ginger group reported a greater improvement with their symptoms than the placebo group.

In addition to symptoms, the authors noted that there were no adverse effects related to full-term delivery.