Ginger

What ginger is

Ginger is the rhizome of Zingiber officinale, a tropical perennial. It is used fresh, dried, as tea and as a spice, and it is also a medicinal plant: the EMA maintains an EU herbal monograph for ginger root, last revised in 2024. As a dietary supplement, powder capsules and extracts are available.

In the BK-Score, human evidence stands at 7 out of 10 points. That means: several randomized trials pointing in the same direction, but small and using different preparations.

How it works

The pungent compounds gingerols and shogaols are considered the active constituents. How exactly they act against nausea is not described in the sources evaluated here.

The exact point of action in humans has not been established. What matters for the assessment is therefore the controlled studies on nausea, not the mechanism.

What the studies show

Viljoen 2014: nausea in pregnancy

The meta-analysis covers 12 randomized trials with 1,278 pregnant women. Ginger improved nausea compared with placebo (mean difference 1.20; 0.56 to 1.84). The number of vomiting episodes did not decrease significantly (p = 0.06). No increased risk of miscarriage emerged, but at 0.65 to 15.11 the confidence interval was very wide. The authors rate the evidence as low.

Chaiyakunapruk 2006 and Tóth 2018: after surgery

Chaiyakunapruk and colleagues pooled 5 randomized trials with 363 patients: with at least 1 g of ginger, the risk of nausea and vomiting in the first 24 hours fell to 0.69 times. In 2018, Tóth and colleagues evaluated 10 studies with 918 patients: the severity of nausea fell significantly (SMD −0.25), frequency and the need for antiemetics decreased, but not significantly.

Crichton 2019 and Lin 2025: chemotherapy

Crichton and colleagues found a 60 percent lower probability of acute vomiting in adults undergoing chemotherapy (3 studies, 301 participants, moderate evidence), but no effect on nausea or delayed vomiting. Lin and colleagues evaluated 35 randomized trials, 22 of them with ginger capsules: in addition to standard antiemetics, severe acute nausea decreased (RR 0.19). In all studies, ginger supplemented standard therapy.

Where the data stop

• Vomiting in pregnancy. Nausea improved, the number of vomiting episodes did not significantly.
• Chemotherapy as a whole. Depending on the analysis, ginger acts on acute vomiting or on severe acute nausea, not on nausea overall and not on delayed vomiting.
• Blood sugar. An umbrella review found HbA1c −0.47 percentage points for ginger in type 2 diabetes, similar to turmeric, but rates the underlying reviews as mostly low to very low in quality.
• Inflammation, immune system, weight. The sources evaluated here do not support a benefit for these; the EMA lists mild joint pain and colds only as traditional use, that is, on the basis of long-standing use rather than clinical studies.

Status, approval and legal

Ginger is a food, a spice and a medicinal plant at the same time. The EMA’s EU herbal monograph (Revision 1, adopted on June 14, 2024) recognizes ginger powder for preventing nausea and vomiting in motion sickness as well-established use; as traditional use it lists mild spasmodic gastrointestinal complaints with flatulence, temporary loss of appetite, mild joint pain and cold symptoms. For medicinal products to prevent travel sickness, the monograph states 1 to 2 g of ginger powder for adults one hour before the start of travel.

As a dietary supplement, ginger may be marketed; there is no official maximum amount. No authorized health claim exists – the EU Commission has put claims on botanical substances on hold in large numbers, the EFSA puts the figure at 1,548. Ginger is not on the WADA Prohibited List 2026.

Safety

According to the EMA monograph, stomach complaints, belching, digestive complaints, heartburn and nausea occur frequently; hypersensitivity reactions are described with unknown frequency. The only contraindication is an allergy to ginger; the monograph lists no known interactions.

On pregnancy, there is a contradiction between the study data and the precautionary principle: the Viljoen meta-analysis found no significantly increased risk of miscarriage, heartburn or drowsiness, and the EMA, too, sees no indication of malformations in the available data. Nevertheless, as a precaution the monograph advises against the use of medicinal products during pregnancy and breastfeeding and against use in under-18s for travel sickness. Nausea in pregnancy calls for supervision by a physician or midwife. In the BK-Score, safety data stand at 7 out of 10: well studied, not free of side effects. This text is information and does not replace medical advice.

Sources

• Viljoen E et al., Nutr J 2014 – meta-analysis, 12 RCTs, 1,278 pregnant women (PMID 24642205)
• Chaiyakunapruk N et al., Am J Obstet Gynecol 2006 – meta-analysis, 5 RCTs, 363 patients, postoperative nausea (PMID 16389016)
• Tóth B et al., Phytomedicine 2018 – meta-analysis, 10 RCTs, 918 patients, postoperative nausea (PMID 30466995)
• Crichton M et al., J Acad Nutr Diet 2019 – meta-analysis, chemotherapy-induced nausea (PMID 31519467)
• Lin CY et al., Cancer Nurs 2025 – meta-analysis, 35 RCTs, chemotherapy-induced nausea (PMID 38625733)
• Li E et al., BMC Complement Med Ther 2025 – umbrella review, medicinal plants in type 2 diabetes (PMID 41029669)
• EMA – Zingiberis rhizoma, EU herbal monograph (Revision 1, 2024)
• EFSA – health claims under Article 13, including 1,548 claims on botanical substances put on hold
• WADA – Prohibited List 2026