Two classes of anti-diabetic drugs have been introduced recently, exenatide injection mimicking glucagon-like peptide-1 (GLP-1) and dipeptidyl dipeptidase-4 (DPP-4 ) inhibitor tablets that hinder the breakdown of GLP-1. These drugs reduce HbA1c by 0·8 to 1·0%, without causing hypoglycaemia, have a beneficial effect on weight, and are an additional option for safe glycaemic control in older diabetic people. In the second of two articles we review the evidence for DPP-4 inhibitors. Part one, covering exenatide, was published in GM2: Heart and Diabetes.