Post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis has been suggested as a model for acute pancreatitis (AP), which allows evaluation of early alterations in the time course of the disease. The influence of the clinical course on procalcitonin (PCT), serum amyloid A (SAA), and several proinflammatory and inhibitory cytokines was evaluated in patients with AP following ERCP. Blood samples were prospectively collected from patients undergoing ERCP. The incidence of ERCP-induced pancreatic damage, defined as abdominal complaints, a threefold increase of serum lipase, and elevation of CRP from <10 to >20 mg/liter was 12.8% (12/94). Only mild clinical courses of acute pancreatitis were observed. PCT significantly increased in subjects with post-ERCP pancreatitis after 24 hr. However, PCT levels did not exceed 0.5 ng/ml in any patient. Interleukin-1 receptor antagonist (IL-1RA) began to differ from baseline 2 hr after ERCP, followed by interleukin-6 (IL-6, 6 hr), solubilized tumor necrosis factor-alpha receptor II (sTNF-alphaRII, 24 hr) and SAA (24 hr). Interleukin 10 (IL-10) showed marked interindividual variations with no obvious peak. Among all parameters evaluated, only peak values of IL-6 and IL-10 showed significant correlations with the reported pain score (r2 = 0.62/0.78), degree of ampullar irritation (r2 = NS/0.87), and the duration of ERCP (r2 = 0.58/0.76). No correlation was found with the volume of the injected contrast agent. We conclude that IL-10 and IL-6 appear to be useful to monitor patients after ERCP. The absence of any PCT elevation in the present study is in accordance with the clinical course of the patients who suffered from mild pancreatic damage without systemic or infectious complications.