As a medicinal supplement, ginger is available in many forms, including teas, syrups, capsules, and liquid extracts. Adults have most commonly used ginger in doses of 0.5-3 grams orally daily for up to 12 weeks. In general, it is not recommended to consume more than 4 g of ginger a day, including food sources. Pregnant women should not take more than 1 g per day.
For optimal results, aim for less than 1500 mg of ginger extract per day. Ginger is also available in tea form or as hard or chewable candies. More research is needed to understand the full effects of ginger on health, but overall, 1 g of real ginger (not ginger-flavored gingerbread cookies or sugar-sweetened soft drinks) during the day seems to be safe and effective. To avoid some of the mild stomach side effects, such as belching, heartburn, or upset stomach, take ginger supplements in capsules or with meals. The Food and Drug Administration (FDA) considers ginger root to be generally safe, with an approved daily intake recommendation of up to 4 g. As the Department of Agriculture points out, 2 teaspoons of ginger provide only 4 calories and no significant amount of any nutrient.
In addition, research shows that ginger can help increase movement through the digestive tract, suggesting that it may alleviate or prevent constipation. Talk to your doctor before taking ginger if you take blood thinners, such as warfarin (Coumadin), clopidogrel (Plavix) or aspirin. More research is needed to determine if ginger is safe or effective for heart disease and diabetes. In China, for example, ginger has been used to aid digestion and treat upset stomachs, diarrhea, and nausea for more than 2000 years. In a study of 261 people with knee osteoarthritis, those who took ginger extract twice a day felt less pain and needed less pain relievers than those who received a placebo. Several studies suggest that ginger may reduce the intensity and duration of nausea during chemotherapy. Some studies also suggest that it may work better than a placebo in reducing some symptoms of motion sickness. One study gave women doses of ginger or a nonsteroidal anti-inflammatory drug (NSAID) during the first three days of their menstrual cycle.
They also called for more human studies to fully understand the effects of ginger on nausea and other gastrointestinal problems. While previous research studied the effects of ginger when consumed, more recent studies focus on the effects of applying ginger oil topically to alleviate pain associated with osteoarthritis.