Many reports described hypoglycemia while using antimicrobial sulfonamides, but this undesired effect has not been reported in cases of intentional self- poisoning. This motivated us to monitor for possible glycemic deterioration in these patients. In 12 patients with acute peroral poisoning with sulfonamides, hypoglycemia defined as blood sugar of less than 2.92±0.49 (2.1-3.4) mmol/L, was present in 5 (41.6%) patients. Despite the high doses of sulfonamides, 9.12±1.04 (6.4-13.6) grams, no life-threatening hypoglycemia was noted. However, these results confirmed the need to monitor patients with this type   of poisoning and to administer glucose solutions to prevent possible hypoglycemia, clinical complications and death.