Garlic has been used as a medicine as long as it has been used as a food, dating back to ancient Egypt. Today, medical research shows garlic may have medicinal applications in two areas: treating high blood pressure and reducing the risk of developing certain types of cancer. While many people take garlic supplements with no ill effects, some do develop side effects such as stomach pain. Always consult with a doctor before using garlic supplements to improve your health.
Gastrointestinal Side Effects
Although garlic is generally regarded as safe, some people experience stomach problems and other gastrointestinal complaints as a side effect. In addition to stomach pain and upset stomach, you may also develop heartburn, nausea, vomiting, diarrhea or a burning sensation in the stomach, mouth or throat, the University of Michigan Health System reports. Because of the potential for these side effects, you should not use garlic if you have stomach or digestive disorders.
Other Side Effects
You may experience other side effects as a result of garlic supplements. Some people develop dizziness, lightheadedness, fatigue, headaches, muscle aches and loss of appetite. The chemical in garlic, allicin, which is responsible for its strong odor, can also cause bad breath and body odor. Aging the garlic can help lessen this effect, but it also may make it less effective in the body, MedlinePlus reports. Before using garlic, ask your doctor about possible side effects.
Other Risks
Some people may develop serious health complications from taking garlic. Because it can cause the blood to thin, people who have bleeding disorders and those scheduled to undergo surgery or major dental work should not take garlic supplements, the National Center for Complementary and Alternative Medicine reports. People who have HIV or AIDS and take protease inhibitors also should not use garlic because it can interfere with the absorption of the medicine. And while garlic in the amounts contained in food poses no risk for women who are pregnant, it may not be safe in supplemental levels and should not be used, MedlinePlus advises.
Safe Dosing
Recommended safe doses of garlic depend on the condition you use it to treat and the form of supplement you use. If you take it to try to prevent colon, stomach or rectal cancer, the recommended dose ranges from 3.5 to 29 g per week. For treating high blood pressure, you can take fresh minced garlic in a dose of 4 g, which roughly equals one clove, MedlinePlus advises. If you take garlic extract, use between 600 mg and 1,200 mg daily, taken in three divided doses. The recommended dose for aged garlic extract is between 600 mg and 7.2 g. Always follow label directions with regard to dosing.
