[Biguanides: reasons for withdrawal of drugs and remaining indications].

The pharmacological properties and the mode of action of biguanides is presented. In Austria, the association of lactic acidosis with biguanide therapy has led to a cancellation of the registration of buformin and phenformin. Only, if all contraindications for biguanide therapy are strictly observed, metformin can be prescribed for the treatment of obese patients with type II diabetes.