*2.4. Safety*

Safety data from an animal study showed that consuming up to 1 g/kg body weight per day of a standardised ethanol extract of ginger had no significant effects on blood glucose, blood coagulation, blood pressure, and heart rate in rats compared to controls [77]. Long-term (35 days) force-feeding of rats with ginger powder up to 2 g/kg body weight was also not associated with any mortality or abnormalities in general conditions, behaviour, growth, and food and water consumption, as shown by Rong et al. [78]. Acute and subacute toxicity studies in rats with an enriched ginger extract (8% gingerols) reported no mortality or clinical signs of toxicity at a dose level of 2000 mg/kg (LD50 > 2000 mg/kg). The repeated administration of ginger extract for 28 days in rats at 1000 mg/kg also did not induce any observable toxic effects, with the no observed adverse effect level (NOAEL) calculated as 1000 mg/kg daily [79].

An oral toxicity study of ginger essential oil (31% zingiberene) in Wistar rats found no adverse effect after 13 weeks of subchronic oral administration. The NOAEL for ginger essential oil was determined to be over 500 mg/kg per day [80]. In another study, Idang et al. [81] performed toxicological assessments of both ginger essential oil and ginger fixed oil in Wistar rats for 60 days and found signs of increased oxidative stress and some forms of pathologies in the livers and spleens of the experimental animals fed up to 0.2 mL/kg of ginger fixed oil. Hence, the authors cautioned against the long-term use of fixed oils derived from ginger. Additional study to validate and confirm the toxicity of ginger fixed oil is required.

In pregnant rats, Weidner and Sigwart [82] also showed that feeding with 1 g/kg body weight of a standardised ginger extract did not cause any maternal or developmental toxicity. In contrast, Wilkinson [83] reported that pregnant Sprague-Dawley rats' exposure to ginger tea increased early embryo loss but enhanced growth in surviving foetuses. Notwithstanding, a systematic review of 14 RCTs and 3 prospective clinical studies over more than 25 years found that ginger use during pregnancy does not pose a risk for the mother and the foetus [84]. Therefore, ginger consumption has no safety concern during pregnancy.
