Open Source Apothecary At Home / Digestion

Nausea and vomiting, including morning sickness

Ginger has real trial evidence, including in pregnancy. It is one of the few herbs where that sentence is true.

remedy

Ginger is the most studied anti-emetic plant, and the evidence clusters in three places: motion sickness, post-operative nausea, and nausea of pregnancy. The effect is modest and consistent, which for nausea is a meaningful thing to have.

The pregnancy evidence is the notable part. Nausea and vomiting of pregnancy is a condition where most herbal remedies have no data at all, because pregnant people are excluded from trials. Ginger has been randomised against placebo in pregnancy at doses commonly around 1 g a day, and it reduces nausea. That makes ginger the rare herbal preparation that can be offered with a citation rather than a shrug — while still being subject to the general rule that any herb in pregnancy should be discussed with an obstetric provider, and that the dose with evidence is around 1 g, not as much as you can tolerate.

The mechanism is not settled. Ginger's gingerols and shogaols have prokinetic effects on the gut and some 5-HT3 antagonism has been proposed; the effect is not blocked by the usual anti-emetic receptor blockers in every study, which suggests more than one route.

Other kitchen measures with a real basis. Small frequent dry meals, cold foods (smell is a major trigger and cold food smells less), avoiding fatty and spicy food, and separating fluids from solids. These are unglamorous and they matter more than the herb for most people.

What to avoid. Pennyroyal, rue, and tansy are traditional emmenagogues and abortifacients and have no place in pregnancy nausea. Cannabis and CBD are not appropriate for pregnancy nausea. And a person who cannot keep fluids down is not a candidate for a tea — that is dehydration and it needs medical care, not a stronger brew.

What the studies found

Preparation

Ginger tea

• 0.5-1 g dried ginger powder, or 2-3 cm of fresh root sliced, to 250 mL water
• Simmer gently, covered, 10 minutes (a short decoction; ginger's aromatics are partly volatile)
• Sip small amounts; cold or at room temperature is often better tolerated than hot

Ginger for a trial-equivalent dose

• The pregnancy trials generally used about 1 g of dried ginger per day, divided into 2-4 doses
• 1 g of dried powder is roughly a level half-teaspoon; measure rather than guess
• Capsules are the form used in most trials

Crystallised ginger

• Convenient, but it is largely sugar. For a dose with evidence, use dried powder or capsules.

Peppermint

• Peppermint tea helps some people and worsens reflux in others
• Peppermint oil capsules have evidence in IBS, not as an anti-emetic

Nausea from a smell trigger

• Cold or room-temperature food, eaten with the window open, is measurably better than hot food
• Small dry meals — crackers, toast — before rising

Cautions and interactions

• In pregnancy, keep to the dose with evidence — around 1 g a day of dried ginger — and tell your obstetric provider.
• Ginger has antiplatelet activity in vitro and may add to anticoagulants. Discuss with the prescriber if on warfarin, a DOAC or an antiplatelet.
• Do not use pennyroyal, rue or tansy for nausea in pregnancy. They are abortifacients.
• Ginger can worsen reflux in some people.
• Do not give honey-based preparations to an infant under 12 months.

When this is not a self-care problem — get help

• In pregnancy: inability to keep fluids down for 24 hours, weight loss, dark scanty urine, or feeling faint — hyperemesis, needs medical care, do not manage at home.
• Vomiting blood, vomiting after a head injury, severe headache with vomiting, or vomiting with a rigid abdomen — emergency care.
• Projectile vomiting in an infant, or green (bile-stained) vomit at any age — emergency care.

Known interactions

• Ginger + warfarin, DOACs or antiplatelets: possible additive bleeding risk.

Related

• Pregnancy and breastfeeding: the honest position
• Motion sickness
• Acute diarrhoea: rehydration first, everything else second
• Fever: what it is for, and when it means something else

Sources

1. Efficacy and Safety of Ginger on Chemotherapy-Induced Nausea and Vomiting: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Cancer nursing 2025; doi:10.1097/NCC.0000000000001355 PubMed 38625733
2. The efficacy and safety of complementary and alternative medicine in the treatment of nausea and vomiting during pregnancy: A systematic review and meta-analysis. Frontiers in public health 2023; doi:10.1152/ajpregu.00344.2004 PubMed 36969661
3. Effects of Ginger Intake on Chemotherapy-Induced Nausea and Vomiting: A Systematic Review of Randomized Clinical Trials. Nutrients 2022; doi:10.1016/j.cbi.2010.02.017 PubMed 36501010
4. Effect of ginger in the treatment of nausea and vomiting compared with vitamin B6 and placebo during pregnancy: a meta-analysis. The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians 2022; doi:10.1080/14767058.2020.1712714 PubMed 31937153
5. The preventive and relieving effects of ginger on postoperative nausea and vomiting: A systematic review and meta-analysis of randomized controlled trials. International journal of nursing studies 2022; doi:10.1016/j.ijnurstu.2021.104094 PubMed 34700257