Ginger appears to be quite good for preventing or treating nausea and vomiting, especially motion sickness, or the nausea of pregnancy.  It also appears of some value for arthritis, although it is best as past of a package of healthy treatments for arthritis.  One-quarter to one-half teaspoon of regular ginger mixed in food is fine or taken in capsules.  It can heartburn in some individuals and mixing it in food may reduce this.  It is portrayed as a wonder drug for everyone by Dr. Andrew Weil in Time Magazine on Oct. 15, 2005.  This is going far beyond the very limited research available.  

A couple animal studies suggest it may be of value for hyperlipidemias (high cholesterol, etc.), high blood glucose, and radiation damage, but the research is scant and no human research at all.  In in vitro studies, it is a good anti-oxidant, but so are numerous other food substances.  At present, it looks like a great spice helpful for some types of nausea and maybe for arthritis.

Ginger Helps Seasickness: DB seven meds in over 1400 voyagers. 80% those not in study got seasick. No difference between various meds although scopolamine had more S-E. Meds included ginger root, cinnarizine, cinnarizine with domperidone, cyclizine, dimenhydrinate with caffeine, meclozine with caffeine, and scopolamine. Schmid, U Zurich, J Travel Med 12/94;1:203; See J Clin Psychiatry 8/98; for treating SSRI withdrawal nausea with ginger root. 59:431; Other studies showing helped vomiting due to cancer drugs in dogs and rats. Has anti-oxidant and anti-inflammatory properties.

Ginger and B6 Helps Pregnancy Nausea: Review study of DB studies of ginger and B6 and found to be effective. Ob Gyn 1/98;91:149; No effect on blood lipids or glucose in another DB study. Another found no anti-thrombotic activity. Another DB no benefit post-op nausea, but one found help nausea from a cancer drug.

Ginger May Help Nausea: Randomized controlled trials for or against the efficacy of ginger for nausea and vomiting. Six studies met all inclusion criteria and were reviewed. Three on postoperative nausea and vomiting were identified and two of these suggested that ginger was superior to placebo and equally effective as metoclopramide. The pooled absolute risk reduction for the incidence of postoperative nausea, however, indicated a non-significant difference between the ginger and placebo groups for ginger 1 g taken before operation (absolute risk reduction 0.052 (95% confidence interval -0.082 to 0.186)). One study was found for each of the following conditions: seasickness, morning sickness and chemotherapy-induced nausea. These studies collectively favored ginger over placebo. Br J Anaesth 2000 Mar;84(3):367-71

Ginger Helps Pregnancy Nausea: A DB PC trial of 250 mg of ginger capsules (about 1/8 teaspoon) four times a day for four days showed a significant benefit in severe hyperemesis gravidarum. Fischer-Rasmussen, European Journal of Obstetrics and Gynaecology and Reproductive Biology 1/1991. Another trial found improvement in nausea with the same ginger dosage and duration, but it only looked at women up to 17 weeks' gestation. Vutyavanich, Obstetrics and Gynecology 4/2001.

Ginger Not Harmful to Developing Fetus: In a study of 187 pregnant women, there was no difference in birth defects between women taking ginger in first trimester for nausea and those not using it. There were significantly more underweight infants in the placebo group. Ginger in capsules was more effective.  Galina Portnoi, University of Toronto, Am J Obstet Gynecol. 11/2003;189:1374-1377

Ginger and B-6 Each Help Pregnancy Nausea: In a DB study of ginger 500 mg t.i.d. (about 1/4 teaspoon three times a day) vs. B-6 10 mg t.i.d. for three days, 138 women with nausea in the first four months of pregnancy were studied.  There were decreases in nausea and vomiting in both groups.  B-6 did non-significantly better with nausea, and ginger did non-significantly better with vomiting. Both symptoms were on average cut by roughly one-third with each supplement.  A randomized comparison of ginger and vitamin B6 in the treatment of nausea and vomiting of pregnancy. Sripramote M, Lekhyananda N. J Med Assoc Thai. 2003 Sep;86(9):846-53

Ginger Not Help Post-op Nausea and Vomiting: Neither ginger 2 grams nor droperidol 1.25 mg helped post-laparoscopy nausea and vomiting. Anesthesia 5/98

Arthritis: Ginger Might Help: Ginger is a traditional Indian remedy for arthritis. In a DB PC crossover study of 29 adults with  gonarthritis, each group received 250 mg four times a day of ginger in capsules for three months with half getting the ginger in the first 3 months and the others in the second 3 months. Two dropped out during ginger administration due to heartburn. By the end of 24 weeks there was a highly statistically significant difference between the VAS of pain and handicap favoring ginger (P<0.001). However, this benefit did not show up during the first 3 months, possibly due to a high improvement in the placebo group. The effects of Zintona EC (a ginger extract) on symptomatic gonarthritis. Wigler I, Grotto I, et al. Tel Aviv University,  Israel. Osteoarthritis Cartilage. 2003 Nov;11(11):783-9. Ed: The study clearly needs to be repeated.

Arthritis: Ginger Helped: In a large 6-week DB PC study of 247 osteoarthritis sufferers, ginger (Zingiber officinale and Alpinia galanga (EV.EXT 77)) twice a day (probably 500 mg) had more reporting a reduction in "knee pain on standing," using an intent-to-treat analysis (63% vs. 50%; P = 0.048). Ginger did better for reduction in knee pain on standing on pain scale estimates (24.5 mm vs. 16.4 mm; P = 0.005), reduction in knee pain after walking 50 feet (15.1 mm vs. 8.7 mm; P = 0.016), and reduction in the osteoarthritis composite index (12.9 mm vs. 9.0 mm; P = 0.087). Change in global status and reduction in intake of rescue medication (Tylenol) were numerically greater in the ginger extract group. Change in quality of life was equal in the 2 groups. Patients receiving ginger extract experienced more gastrointestinal (GI) adverse events than did the placebo group (59 patients versu.s. 21). GI adverse events were mostly mild. Effects of a ginger extract on knee pain in patients with osteoarthritis. Altman RD, Marcussen KC. University of Miami, Florida, USA. Arthritis Rheum. 2001 Nov;44(11):2531-8.

Arthritis: Ginger Benefit Weak in Short Study: In a brief DB PC crossover study with patients on ginger for 3 weeks, ibuprofen for 3 weeks and placebo for 3 weeks with 1 week washouts, ibuprofen did clearly better for pain relief with ginger only somewhat better than placebo (P< 0.00001). A randomized, placebo-controlled, cross-over study of ginger extracts and ibuprofen in osteoarthritis. Bliddal H, Rosetzsky A, et al. Frederiksberg Hospital, Copenhagen, Denmark. Osteoarthritis Cartilage. 2000 Jan;8(1):9-12.

Arthritis and Muscle Pain: Ginger Used for Arthritis and Muscular Discomfort: In a non-scientific open report of 56 patients (28 with rheumatoid arthritis, 18 with osteoarthritis and 10 with muscular discomfort) using powdered ginger, more than three-quarters of arthritis patients reported, to varying degrees, relief in pain and swelling. All the patients with muscular discomfort experienced relief in pain. None reported adverse effects during the period of ginger consumption which ranged from 3 months to 2.5 years. Ginger inhibits prostaglandin and leukotriene biosynthesis. Ginger (Zingiber officinale) in rheumatism and musculoskeletal disorders. Srivastava KC, Mustafa T., Odense University, Denmark. Med Hypotheses. 1992 Dec;39(4):342-8. Ed: Powdered ginger can be purchased very cheaply in some Oriental food stores. 1 g/day is about 1/2 teaspoon.  This can easily be added to food and may cause less gastritis that way, if the above report is correct.

No Value for Nausea After Laparoscopic Surgery: In a DB PC study of 108 patients undergoing gynecological laparoscopic surgery under general anaesthesia, oral placebo did as well as or better than ginger BP 0.5g or ginger BP 1.0g, all with oral diazepam premedication, one hour prior to surgery. The incidence of nausea and vomiting increased slightly but nonsignificantly with increasing dose of ginger. The incidence of moderate or severe nausea was 22, 33 and 36%, while the incidence of vomiting was 17, 14 and 31% in groups receiving 0, 0.5 and 1.0g ginger, respectively (odds ratio per 0.5g ginger 1.39 for nausea and 1.55 for vomiting). A double-blind randomized controlled trial of ginger for the prevention of postoperative nausea and vomiting. Arfeen Z, et al. Flinders Medical Centre, Bedford Park, S.A. Anaesth Intensive Care. 1995 Aug;23(4):449-52.

Cholesterol and Glucose Lowering Effect in Rat Study: In a 20-day study of ginger (Zingiber officinale) (200 mg/kg) fed to diabetic rats, there was an antihyperglycemic effect (P < 0.01). It also lowered serum total cholesterol, triglycerides and increased the HDL-cholesterol levels when compared with pathogenic diabetic rats (P < 0.01). The results of test drug were comparable to gliclazide (25 mg/kg, orally), a standard antihyperglycemic agent. Zingiber officinale appears to be able to protect the tissues from lipid peroxidation. Effect of ethanolic extract of Zingiber officinale on dyslipidaemia in diabetic rats. Bhandari U, et al. Hamdard University, New Delhi, India. . J Ethnopharmacol. 2005 Feb 28;97(2):227-30.