People taking insulin need to use caution when consuming medicinal amounts of garlic, because garlic may help to regulate blood sugar levels
Use with anticoagulants could increase risk of bleeding
If preparing garlic-oil combination, it is important to store properly—not at room temperature—and to always add acid to prevent botulism spores from growing
References and recommended readings
MedlinePlus. Garlic. Available at: http://www.nlm.nih.gov/medlineplus/druginfo/natural/300.html. Accessed March 29, 2011.
National Center for Complementary and Alternative Medicine. Garlic. Available at: http://nccam.nih.gov/health/garlic/ataglance.htm. Accessed March 29, 2011.