# Ginger: Panacea or Consumer's Hype?
## 2 Pharmacology of Ginger
### Biological Activity
#### 2.3.2 Anti-Emetic Activity  
The anti-emetic activity of ginger is best documented in cases of pregnancy, with various clinical trials showing its practical utility [43]. In eleven out of the twelve trials conducted, ginger powder, at a daily dose \(\geq\)1 g, was able to reduce or eliminate _hyperemesis gravidarium_[44] and the episodes of nausea vomiting associated with pregnancy [45; 46; 47; 48; 49; 50; 51; 52; 53; 54].  
The use of ginger as an antiemetic is also reported for motion and post-operative sickness cases, but studies are somewhat scarcer. Regarding motion sickness, the most relevant trial was conducted on a group of 80 navy cadets, with 40 taking 1 g of ginger powder in a single dose and the other 40 taking placebo. The cadets were monitored for 4 h following ingestion. The ginger-treated group had no emesis and exhibited a strong reduction of symptoms, such as cold sweating and vertigo, in comparison with the placebo group; note that in the placebo group there were also a few incidences of vomiting [55; 56]. Ginger's motion-sickness preventive action in individuals with extreme or very high susceptibility to this condition was demonstrated by two studies which resorted to motion-induced sickness, that is, the volunteers were placed in tilted rotating chairs [57; 58]. In one of these, 12 young volunteers were given 1.9 g of ginger powder, while another 12 received dimenhydrinate (an anti-histamine and CNS depressant that blocks vertigo impulses). Results show ginger is superior to dimenhydrate in preventing the gastrointestinal symptoms of motion sickness [57]. The second study followed double-blind, randomised, placebo-controlled protocols to compare the action of two doses of ginger. 1 g of ginger powder was shown to be as effective as 2 g of ginger powder in reducing motion-induced nausea, with both doses being significantly more effective than the placebo [58]. A third trial, sponsored by NASA, tested the effects of ginger on healthy volunteers, that is, people not particularly prone to motion sickness. A dose of 1 g of ginger powder was compared with 0.6 g of scopolamine (an anti-emetic API) and the effectiveness was measured by the ability of the volunteers to tilt their head (without utter discomfort) while they were spinning on the rotating chair. The results of the group taking ginger (\(n=8\)) were poor, volunteers performing very close to the placebo group; moreover, the ginger group scored much worse than that of scopolamine (also with \(n=8\)) [59]. Nevertheless, this form of measuring the resilience to sickness may not be the most clinically relevant.  
In post-operative sickness, 1 g of ginger (taken before the operation) was demonstrated by two case studies to reduce the incidence and severity of nausea to roughly half of that observed in the placebo group [60; 61]. Ginger may also be useful in combination therapy with conventional antiemetic drugs to prevent acute nausea resulting from chemotherapeutic drugs, as demonstrated by a large scale (\(n=576\)) double-blind study [62]. Also noteworthy is a single-blind, randomised, controlled, cross-over study, conducted in two oncology clinics on 60 women taking chemotherapeutic drugs for breast cancer and treated with ginger oil, inhaled continuously from an aromatherapy necklace. The results of this study showed that patients, after the fifth day of treatment with ginger oil, had higher gastrointestinal comfort and were thus able to ingest food in amounts that were closer to their daily energetic requirements than those of the placebo group (note: these were wearing a necklace with matching odour but no ginger oil) [63].