Hypoglycaemic medication forms a disparate group of therapeutic compounds including insulin, the sulphonylureas and biguanides. They are all designed to prevent hyperglycaemia and in general are well tolerated. Careful prescribing practice and patient education by the physician can do much to reduce the risk of adverse effects from diabetic therapy. However, the presentation of adverse effects, together with accidental and non-accidental overdose, is a frequent clinical problem. Furthermore, the possible impairment of hypoglycaemic awareness in patients prescribed human insulin has added complexity to diabetic management. The cardinal features of insulin overdose are hypoglycaemia and hypokalaemia. The sulphonylureas predominantly cause hypoglycaemia, while the biguanides may precipitate lactataemia and acidosis. Recognition of hypoglycaemia is therefore crucial in avoidance of toxicity. Intravenous dextrose is the mainstay of therapy following gut decontamination (for the oral agents). The efficacy of glucagon is dependent on hepatic glycogen stores and should therefore be used with caution. Diazoxide is not recommended. More recently, octreotide has been shown to be effective in sulphonylurea overdose. Patients should be admitted and monitored with serial blood sugar measurements for a minimum of 1 to 2 days as clinically warranted.