The STOP-NIDDM Trial has shown that acarbose treatment in subjects with impaired glucose tolerance is associated with a significant risk reduction in the development of diabetes, hypertension and cardiovascular complications. Kaiser and Sawicki have accused the investigators of the STOP-NIDDM Trial of major biases in the conduct of the study, of manipulating the data and of conflict of interest. The aim of this paper is to present data and explanations refuting these allegations. In the STOP-NIDDM Trial, 61 subjects were excluded from the efficacy analysis before unblinding for legitimate reasons: failure to satisfy major entry criteria (n=17) and lack of post-randomisation data (n=44). Blinding and randomisation were carried out by an independent biostatistician. Titration of placebo/acarbose is well described in the protocol and in the study design paper. Of the study population, 9.3% had a fasting plasma glucose of > or =7.0 mmol/l at screening and could have been diabetic according to the new diagnostic criteria. However, even if these subjects are excluded, patients having acarbose treatment still saw a significant risk reduction in the development of diabetes (p=0.0027). The changes in weight are consistent in different publications and are related to different times of follow-up and assessment. Weight change does have an effect on the development of diabetes, but acarbose treatment is still effective even after adjusting for this (p=0.0063). The cardiovascular endpoints were a clearly designated assessment in the original protocol, and only those defined in the protocol and ascertained by the independent Cardiovascular Event Adjudication Committee were used in the analysis. Hypertension was defined according to the most recent diagnostic criteria. The STOP-NIDDM Trial results are scientifically sound and credible. The investigators stand strongly behind these results demonstrating that acarbose treatment is associated with a delay in the development of diabetes, hypertension and cardiovascular complications in a high-risk population with IGT.