Taking too much medicinal ginger can cause confusion, dizziness, sleepiness and irregular heart rhythms, according to eMediicineHealth. People taking heart medications should talk with a medical professional before using ginger. Taking ginger in high doses may make some heart conditions worse, states WebMD.
Dosages used in scientific studies include 250 milligrams of ginger four times a day for morning sickness and 1 to 2 grams of ginger root in powder form before undergoing anesthesia.to prevent nausea and vomiting after surgery, according to WebMD. Studies using ginger to relieve arthritis symptoms include 170 milligrams taken three times a day and 250 milligrams taken four times a day, depending on the product. Most people can use ginger safely. Mild side effects include general stomach discomfort and heartburn.