Several studies demonstrated a significant reduction of contrast-induced nephropathy (CIN; definition: increase in serum creatinine of >=0.5mg/dl and/or >=25% increase within 48h after contrast-medium) by acetylcysteine (A) or theophylline (T). However, the results are contradictory. Therefore, it was the aim of our double-blind study to compare the effects of A, T, a combination of A and T (A+T), and placebo (P).